UC-NRLF 


B   4   305   335 


CHAPTERS 

IN 

GENERAL  PSYCHOLOGY 


BY 

STEVENSON  SMITH 

PROFESSOR  OF  PSYCHOLOGY  IN  THE  UNIVERSITY  OF  WASHINGTON 

AND 

EDWIN  GUTHRIE 

ASSISTANT  PROFESSOR  OF  PSYCHOLOGY  IN  THE  UNIVERSITY  OF  WASHINGTON 


Revised  Edition 


1921 

University  of  Washington  Pvess 

'Seattle 


CHAPTERS 

IN 

GENERAL  PSYCHOLOGY 


BY 

STEVENSON  SMITH 

PROFESSOR  OF  PSYCHOLOGY  IN  THE  UNIVERSITY  OF  WASHINGTON 

AND 

EDWIN  GUTHRIE 

ASSISTANT  PROFESSOR  OF  PSYCHOLOGY  IN  THE  UNIVERSITY  OF  WASHINGTON 


Revised  Edition 


1921 

University  of  "Washington  Press 

Seattle 


EDUC. 

PSYCH. 

LIBRARY 


CONTENTS 

I     The  Elements  oe  Behavior 5 

Behavior  dependent  on  bodily  structure 6 

Classes  of  sense  organs 8 

The  exteroceptors 9 

The  interoceptors 19 

The  proprioceptors 20 

The  nervous  system 21 

Regulatory  character  of  responses 27 

Delayed  utility  of  responses 27 

Apparent  absense  of  utility  of  some  responses 28 

Orientation,  locomotion,  and  intervention 28 

Internal  responses 30 

The  action  of  a  stimulus-response  mechanism 32 

Weber's  law 34 

The  interaction  of  stimulus  response  mechanisms 36 

Compromise  responses 38 

II     Instinct 39 

Classification  of  instincts  according  to  utilities 40 

Individual  differences 46 

III  Learning  49 

Positive  adaptation 49 

Negative  adaptation 52 

Transitory  changes  of  threshold  during  a  single  practice 

period 55 

The  conditioned  response 57 

Facilitating  effect  of  conditioning  stimuli 62 

Neural  basis  of  the  conditioned  response 63 

The  serial  response 65 

The  effects  of  practice  on  the  serial  response 68 

Forgetting     72 

Whole  and  part  learning 75 

Results  of  the  distribution  of  practice 76 

Trial  and  error 76 

The  shortening  of  a  trial  and  error  series  into  a  final  habit 

response 79 

Imitation   87 

IV  The  Behavior  oe  Babies 90 

V    Perception    103 

Perception  and  speech 106 

Compromise  responses  in  perception 112 

(3) 


CONTENTS 

Perceptions  from  simultaneous  stimuli 112 

Space  perception 113 

Visual  space  perception 114 

Visual  perception  of  objects 118 

Auditory  space  perception 119 

Auditory  perception  of  objects 120 

Olfactory  perception 121 

Kinaesthetic  and  static  perception 123 

Touch  perception 124 

Time  perception 124 

Judgment 126 

Conviction  and  belief 130 

VI     Human   Motives  132 

The  delayed  reaction 132 

Preparatory  and  consummatory  responses 135 

The  wish  __.„ 137 

Attention  137 

Volition        138 

Drive    141 

Sublimation  144 

Conflict    146 

Overcorrection ' 147 

Play     148 

VII     Social  Psychology 152 

Fellow  man  as  a  constant  situation 152 

Other  prevalent  situations 153 

Formation  of  habits  in  common 155 

The  spread  of  tradition 160 

Opinion  spreads  from  mouth  to  mouth 163 

Human  institutions 164 

VIII     Consciousness 166 

Consciousness  and  the  nervous  system 167 

Sensation    168 

Emotion  and  affection 171 

After-images 171 

Association  of  ideas 173 

Imagination       175 

Attention 176 

Perception 177 

The  unconscious 177 

List  of  authors-    179 

4 


CHAPTER  1 
THE  ELEMENTS  OF  BEHAVIOR 

Psychology  takes  the  common  sense  view  that  any  ani- 
mal is  a  physical  object  in  a  world  of  physical  objects.  It  as- 
sumes that  all  these  objects  act  upon  each  other  in  the  ways 
described  by  physics,  chemistry  and  physiology.  It  considers 
man's  behavior  as  a  physical  event  which  can  be  analyzed 
into  bodily  movements.  In  this  sense  man's  behavior  is 
mechanical  and  his  body  is  a  machine. 

Any  attempt  to  construct  a  machine  that  would  respond 
as  elaborately  and  appropriately  as  do  animals  to  the  world 
of  surrounding  objects  must  certainly  fail.  This  is  not  because 
the  behavior  of  animals  involves  new  and  mysterious  forces 
lacking  elsewhere  in  nature  but  because  their  structure  is  too 
complex  to  be  duplicated. 

It  must  not  be  supposed  that  thinking  is  denied  by  physi- 
ological psychology.  A.  behavioristic  description  of  man's 
mind  in  no  way  contradicts  the  common  sense  assumption 
that  men  are  conscious.  We  shall  first  find  out  what  man  does, 
and  under  what  circumstances  he  does  it,  because  this  is  open 
to  observation  and  may  be  stated  exactly.  With  this  science 
of  behavior  as  a  groundwork,  we  shall  later  undertake  an 
account  of  consciousness. 

All  that  we  can  observe  in  our  fellow  man  is  his  behavior. 
He  moves  his  body  and  its  appendages  as  he  goes  from  place 
to  place  or  as  he  rearranges  the  objects  about  him.  In  con- 
versation he  contracts  the  necessary  muscles  and  is  heard  to 
speak.  In  emotional  expression  he  blushes,  his  pulse  is  altered, 
his  hands  grow  cold,  his  liver  gives  up  its  sugar,  and  we  see 
shame,  anger,  or  anxiety.  His  thoughts,  as  such,  are  known 
to  no  one  but  himself. 

Any  physical  object  is  at  all  times  being  acted  upon  by 
forces  which  affect  it  in  various  ways.     The  stone  lying  in 


6  ELEMENTS  OF  BEHAVIOR 

the  road  is  moved  about  by  the  impact  of  rain,  warmed 
and  expanded  by  the  sun,  and  scratched  by  the  wheels  of 
passing  vehicles.  Its  responses  to  these  forces  are  simple  and 
easily  predicted  because  of  the  simplicity  of  its  structure. 

If  we  consider  not  only  the  stone  in  the  road  but  also 
the  gopher  who  sits  beside  it,  we  find  the  same  forces  acting. 
The  light  reflected  from  surrounding  objects  falls  on  both 
alike,  both  are  struck  by  the  rain  or  warmed  by  the  sun,  but. 
the  result  of  the  action  of  these  forces  on  the  gopher  is  behav- 
ior quite  different  from  the  behavior  of  the  stone.  The  light 
rays  reflected  from  the  approaching  vehicle  cause  him 
to  scurry  away  and  those  reflected  from  food  cause  him  to 
approach.  The  impact  of  rain  may  move  him  toward  the 
source  of  impact  rather  than  away  from  it.  Though,  like 
the  stone,  he  is  a  physical  object,  he  is  not  merely  buffeted 
about  by  his  environment. 

Behavior  Dependent  on  Bodiey  Structure 

The  difference  between  the  behavior  of  animals  and  the 
behavior  of  inanimate  objects  depends  upon  the  fact  that 
animals  possess  specialized  structures.  The  most  important 
of  these  structures  are  the  sense  organs  (receptors),  the  mus- 
cles and  glands  (effectors),  and  the  nervous  system.  The  sense 
organs  are  placed  in  parts  of  the  body  where  they  are  exposed 
to  the  action  of  physical  forces.  Because  the  various  kinds 
of  sense  organs  differ  from  each  other  in  structure,  some  are 
provoked  to  action  by  one  kind  of  physical  force  and  some  by 
another.  The  physical  forces  which  arouse  the  sense  organs 
to  action  are  called  stimuli. 

Light  has  an  effect  upon  the  eye  which  it  does  not  have 
upon  the  ear  or  upon  the  skin.  Gases  emanating  from  a  flower 
act  only  upon  the  olfactory  sense  organs.  The  stimulus  which 
commonly  arouses  the  sense  organ  to  its  characteristic  func- 
tion is  called  the  adequate  stimulus.  Many  sense  organs  may 
be  stimulated  by  pressure  or  an  electric  current  in  addition 
to  their  more  frequently  received  stimuli. 


ELEMENTS  OF  BEHAVIOR  7 

The  physical  forces  which  stimulate  the  sense  organs 
differ  in  kind.  Light,  sound,  heat,  impact,  gravity,  are  a  few 
of  these  and  each  acts  upon  some  sense  organ  or  another.  All 
stimuli  may  vary  in  intensity,  and  their  effect  upon  sense 
organs  may  vary  correspondingly. 

Sense  organs  are  connected  with  distant  muscles  and 
glands  by  nerve  structures.  Along  these  nerve  structures  pass 
nervous  impulses  which  result  from  the  stimulation  of  the 
sense  organs  and  which,  on  reaching  muscles  and  glands,  may 
cause  muscular  contraction  or  glandular  secretion.  It  follows 
that  any  response  to  a  stimulus  can  occur  only  when  there  is 
a  conduction  pathway  established  between  the  sense  organ 
receiving  the  stimulus  and  the  muscles  concerned  in  the  re- 
sponse.   Such  a  pathway  is  called  a  neural  arc. 

The  nervous  system  contains  millions  of  nerve  cells  called 
neurones.  These  are  microscopic  in  cross-section  but  are  oc- 
casionally as  much  as  two  feet  or  more  in  length.  Each  neu- 
rone consists  of  a  cell  body  from  which  extend  branching 
processes  which  may  lie  adjacent  to  other  cells.  The  points 
of  contact  so  established  offer  varying-  resistance  to  the  pas- 
sage of  nervous  impulses  from  one  cell  to  another.  A  con- 
nection between  two  neurones  which  permits  the  passage  of  a 
nervous  impulse  is  called  a  synapse.  The  repeated  passage  of 
an  impulse  through  a  synapse  is  supposed  to  increase  the  con- 
ductivity of  the  synapse.  Some  synapses  are  present  at  birth, 
some  occur  in  the  maturation  of  the  nervous  system,  whereas 
others  are  formed  in  the  course  of  learning. 

The  great  number  of  neurones  and  the  complexity  of  their 
connections  account  for  the  fact  that  an  impulse  leaving  a 
particular  sense  organ  may  find  its  way  to  one  group  of 
muscles  at  one  time  and  to  another  group  of  muscles  at  another 
time. 

The  muscles  and  glands  are  the  effectors  or  organs  of 
response.  They  are  so  situated  and  so  connected  by  nervous 
structures   that   their   responses   are    coordinated   and   meet 


8  ELEMENTS  OF  BEHAVIOR 

suitably  most  situations.  They  are  so  connected  with  sense 
organs  that  their  action  is  appropriate  to  the  stimulus.  The 
nervous  impulse  which  is  originated  by  placing  something  in 
the  baby's  hand  finds  its  way  to  the  muscles  which  cause  the 
fingers  of  that  hand  to  grip  the  object.  Without  such  estab- 
lished pathways  of  conduction,  behavior  would  be  inappro- 
priate. 

A  significant  characteristic  of  all  sense  organs  is  that 
they  are  most  sensitive  to  situations  which  affect  the  life  pro- 
cesses of  the  animal.  This  is  accomplished  in  two  ways,  first 
by  the  position  of  the  sense  organs  in  the  body,  and  second  by 
their  structure  and  by  the  nature  of  their  adequate  stimuli. 
For  example,  the  eyes  are  so  placed  in  the  front  of  the  body  as 
to  receive  stimuli  from  objects  which  the  animal  is  approach- 
ing. Placed  at  the  rear  they  would  be  less  useful.  The  tongue 
has  a  strategic  position,  as  all  food  must  pass  its  inspection 
before  being  swallowed,  and  the  sense  organs  of  taste  are 
affected  as  are  no  other  parts  of  the  body  by  chemical  stimuli, 
which  are  indicative  of  the  food  value  of  any  substances  taken 
into  the  mouth. 

Classes  or  Sense  Organs 

Sense  organs  are  divided  into  three  kinds  according  to 
their  location  in  the  body,  the  exteroceptors,  the  interoceptors, 
and  the  proprioceptors.1  Those  on  the  outer  surface  of 
the  body  which  respond  to  external  stimuli  are  called  extero- 
ceptors. These  are  the  sense  organs  in  the  skin  which  respond 
to  touch,  temperature,  and  destructive  stimuli,  and  along  with 
these  the  sense  organs  in  the  eyes,  ears,  and  nose.  The  eyes, 
ears,  and  nose  are  also  called  distance  receptors  because  they 
respond  to  stimuli  whose  origin  is  commonly  at  a  distance,  a 
classification  recognized  by  as  early  a  writer  as  Aristotle.2 

In  addition  to  the  external  surface  there  is  the  surface  of 
the  enteric  tract  which  consists  of  the  mouth,  pharynx,  oeso- 
phagus^ stomach  and  intestines.    This  surface  is  also  provided 

1  Sherrington,   The  Integrativt     lotion  of  the  Nervous  System,  Lecture  9. 

2  Aristotle,   de  eensu,  43Gb. 


ELEMENTS  OF  BEHAVIOR  9 

with  sense  organs  and  these  are  called  interoceptors.  When 
parts  of  the  external  world  are  taken  into  the  enteric  tract  as 
food  the  interoceptors  are  stimulated  by  them  and  the  animal's 
behavior  is  adjusted  to  their  presence.  The  mouse  which  is 
outside  a  cat  stimulates  the  cat's  exteroceptors  and  the  cat 
responds  in  a  conspicuous  and  characteristic  way.  Once  the 
mouse  is  transferred  to  the  cat's  enteric  tract,  the  cat's  reac- 
tions are  less  obvious  but  none  the  less  important.  Movements 
of  rejecting  food,  of  swallowing  and  of  peristalsis,  the  secre- 
tion of  digestive  fluids,  and  much  of  the  animal's  observable 
behavior  result  directly  from  the  stimulation  of  interoceptors. 
Sense  organs  occur  not  only  on  the  outer  and  the  inner 
surfaces'  of  the  animal  but  are  found  also  deeply  imbedded  in 
the  body  tissue.  These  deeply  imbedded  sense  organs  are  called 
proprioceptors.  Among  the  contractile  muscle  fibers  are  sit- 
uated receptors  which  are  stimulated  by  muscle  tension.  Other 
receptors  in  the  tendons  receive  stimuli  in  a  similar  way.  The 
walls  of  bloodvessels  are  also  supplied  with  sense  organs  so 
that  circulatory  changes  affect  the  animal's  behavior.  In  the 
head  are  located  the  semicircular  canals  and  the  organs  of 
static  sense,  which  are  stimulated  by  the  movement  or  by  the 
position  of  the  animal.  The  proprioceptors  are  all  important 
in  making  possible  the  coordination  of  bodily  movements.3 

The  Exteroceptors 

The  most  highly  developed  of  the  exteroceptors  are  the 
distance  receptors,  namely  the  organs  of  vision,  hearing,  and 
smell.4 

The  Bye.  Anyone  having  an  acquaintance  with  the  cam- 
era will  find  it  easy  to  understand  the  mechanism  of  the  eye. 
Light  passes  into  the  eye  through  a  diaphragm  called  the  iris, 
just  inside  the  anterior  wall  of  the  eye,  which  is  called  the 
cornea.    Behind  the  iris  is  the  lens  and  behind  the  lens,  on  the 

3  On   the  classes   of  sense   organs   and   their   functions   see   Sherrington,    Integrative   Action   of 
the  Nervous  System,  Lecture  9. 

4  For    a   more   detailed    account    of    the    structure    and   function    of   sense   organs   and    nervous 
system  see  Ladd  and  Woodworth,    Elements  of  Physiological  Psychology. 


10 


ELEMENTS  OF  BEHAVIOR 


inner  surface  of  the  eye's  globe-like  wall,  is  the  sensitive  retina. 
The  internal  cavity  of  the  eye  is  filled  with  a  transparent 
mass.  That  in  front  of  the  lens  is  called  the  aqueous  humor 
and  that  behind  the  lens,  the  vitreous  humor.  As  we  view  our 
own  eye  in  the  mirror  we  see  at  the  center  a  black  spot,  the 
pupil,  surrounded  by  a  pigmented  ring,  the  iris.  The  pupil  is 
a  hole  in  the  iris  and  appears  black  because  it  is  an  opening  into 
the  unlighted  interior  of  the  eye.  It  is  the  color  of  the  iris  to 
which  we  refer  when  we  speak  of  brown  eyes  or  blue  eyes.  Out- 
side the  circle  of  the  iris  is  the  white  sclerotic,  continuous  with 
the  cornea,  which  with  the  cornea  constitutes  the  external  wall 
of  the  eye.  (See  Figure  1.) 


Figure  1 — Schematic  diagram  of  a  section  through  the  eye. 

By  means  of  six  external  muscles  the  eyeball  is  moved 
about  in  its  socket,  and  in  this  way  a  person  looks  up  or  down, 
to  the  right  or  the  left,  converges  the  two  eyes  in  fixating  a 
near  object  or  so  directs  them  that  the  axes  of  vision  are 


ELEMENTS  OF  BEHAVIOR  11 

almost  parallel  in  fixating  a  distant  object.     To  some  extent 
the  eye  maybe  rotated  about  the  axis  of  vision.  (See  Figure  2.) 


Figure  2 — Diagram  of  the  position  of  the  external  muscles  which  move  the  eye  ball. 

The  iris  is  a  doughnut  shaped  muscle  containing  for  the 
most  part  circular  muscle  fibres.  When  these  fibres  contract, 
the  hole  in  the  center,  the  pupil,  becomes  smaller.  When  the 
radiating  fibres  which  it  contains  contract,  the  pupil  becomes 
larger  .  For  near  vision  and  when  stimulated  by  bright  light 
the  pupil  becomes  smaller.  For  distant  vision  and  in  dim 
light  the  pupil  becomes  larger. 

The  crystalline  lens  is  suspended  all  around  its  margin  by 
the  suspensory  ligament  which  connects  it  with  another 
doughnut  shaped  muscle  called  the  ciliary  muscle.  When  the 
circular  fibres  of  this  muscle  contract,  the  tension  on  the  sus- 
pensory ligament  is  decreased  and,  due  to  its  own  elasticity, 
the  lens  becomes  more  convex.  In  this  shape  it  focuses  rays 
of  light  from  near  by  objects  so  that  the  images  of  these  objects 
are  clearly  defined  on  the  retina  and  the  images  of  distant 
objects  are  blurred.  When  the  circular  fibres  of  the  ciliary 
muscle  are  relaxed  and  the  radial  fibres  contracted,  the  sus- 
pensory ligament  is  under  greater  tension  so  that  the  lens 
becomes  less  convex  and  the  images  of  distant  objects  are 
clearly  defined  on  the  retina,  the  images  of  nearby  objects 


12  ELEMENTS  OF  BEHAVIOR 

being  blurred.  When  the  eyelids  are  closed  and  the  eye  is  at 
rest  the  circular  fibres  are  relaxed  and  the  lens-  takes  on  this 
less  convex  shape,  that  is,  the  eye  is  accommodated  for  distant 
vision. 

Accommodation  for  near  vision,  then,  involves  a  smaller 
hole  in  both  the  iris  and  the  ciliary  muscle  and  this  is  brought 
about  by  the  contraction  of  the  circular  fibres  in  each.  For 
this  reason  accommodation  for  near  vision,  due  to  the  stimula- 
tion of  sense  organs  in  these  muscles,  gives  us  a  sensation  of 
muscle  strain.  In  distant  vision  and  dim  light,  where  the 
circular  fibres  are  relaxed,  such  sensations  are  practically 
absent. 

The  adequate  stimuli  to  the  eye  are  ether  vibrations  whose 
frequency  is  more  than  450  billion  vibrations  per  second  and 
less  than  790  billion.  Lights  of  different  color  have  different 
vibration  frequencies  and  intense  lights  have  a  greater  ampli- 
tude of  vibration  than  have  dim  lights.  White  sunlight  con- 
tains a  mixture  of  rays  of  all  possible  vibration  frequencies  to 
which  the  eye  is  sensitive.  Light  emanating  from  a  source 
such  as  the  sun  or  a  candle  either  enters  the  eye  directly  or 
impinges  upon  the  surfaces  of  objects,  from  which  it  is  re- 
flected into  the  eye. 

Light  passing  through  the  cornea,  the  aqueous  humor, 
the  lens,  and  the  vitreous  humor  reaches  the  retina.  In  the 
retina  are  found  chemical  substances,  which  change  their 
composition  when  acted  upon  by  light,  and  cell  structures, 
some  of  which  are  affected  by  these  chemical  changes.  Ex- 
actly what  takes  place  in  the  retina  is  not  known,  but  we  have 
reason  to  believe  that  the  pattern  of  the  image  focussed  upon 
the  retina  sets  up  various  changes  in  the  photo-chemical  sub- 
stances and  that  these  changes  affect  adjacent  cell  structures. 
This  is  the  stimulation  which  gives  rise  to  nervous  impulses. 

Apart  from  supporting  tissue,  the  cell  structure  of  the 
retina  is  made  up  of  nerve-cell  bodies  whose  long  processes,  or 
axones,  constitute  the  optic  nerve ;  of  other  nerve  cells  whose 


ELEMENTS  OF  BEHAVIOR 


13 


function  it  is  to  connect  adjacent  parts  and  layers  of  the 
retina ;  and  of  the  rods  and  cones  which  may  be  regarded  as 
the  actual  sense  organs  for  vision.  (See  Figure  3.)  The  rods 
respond  to  dim  light,  whereas  the  cones  respond  only  to  in- 
tense light.  Colored  light  and  white  light  affect  the  rods  in 
the  same  way,  no  color  vision  resulting  from  such  stimulation.5 

lOireeTion      I 
J,  of  li^hT     | 


Geus 


Bipolar  CeUs 


Figure  3 — Schematic  representation  of  a  section  through  the  retina,  showing  the 
position  of  rods  and  cones,  the  layer  of  connecting  neurones,  and  the  direc- 
tion of  fibres  of  the  optic  nerve. 


On  the  other  hand  the  cones  give  a  specialized  response  to 
white  light  and  to  lights  of  different  colors  and  it  is  by  means 
of  the  cones  that  we  distinguish  one  color  from  another. 

The  rods  are  lacking  in  the  fovea,  or  that  portion  of  the 
retina  which  is  directly  opposite  the  pupil.  At  night  when  an 
image  of  a  faint  star  falls  upon  the  fovea,  where  there  are  no 
rods,  it  cannot  be  seen,  but  it  becomes  visible  when  we  glance 
to  one  side  and  so  cause  its  image  to  be  displaced  toward  the 
periphery,  which  is  so  well  supplied  with  these  sense  organs 

5  For  the  various  theories  of  color  vision  see  Ladd   and  Woodworth,   pages  340ff. 


14  ELEMENTS  OF  BEHAVIOR 

for  dim  light.  The  fovea  is  richly  supplied  with  cones  and 
is  the  so-called  area  of  distinct  vision.  The  image  of  the  print 
which  is  being  read  falls  upon  the  fovea  and  the  print  could 
not  be  read  as  well  if  its  image  were  to  fall  upon  the  peri- 
pheral, or  outer,  margin  of  the  retina.  The  extreme  periphery 
contains  only  rods,  and  for  this  reason  any  object  casting  its 
image  there  appears  to  be  without  color. 

When  the  eye  has  been  exposed  to  intense  light  the  rods 
become  fatigued  and  do  not  function  in  twilight  until  after  a 
period  of  rest.  For  this  reason,  if  we  enter  a  darkened  thea- 
tre in  the  daytime  we  grope  blindly  for  the  seat,  but  if  we  have 
come  in  from  the  dimly  lighted  street  at  night  we  find  our 
way  about  without  difficulty.  In  the  dark-room  it  may  require 
a  stimulus  8,000  times  as  great  to  elicit  a  response  from  a  light 
fatigued  eye  as  is  required  to  secure  a  response  from  the 
thoroughly  rested  eye.  This  is  true,  of  course,  only  of  parts 
of  the  retina  where  rods  are  found.  The  unfatigued  eye  is 
sometimes  ambiguously  called  a  dark-adapted  eye. 

Ordinarily  both  eyes  are  used  in  vision,  and  are  so 
directed  toward  a  part  of  any  object  which  is  looked  at  that 
the  right  eye  image  and  the  left  eye  image  fall  on  correspond- 
ing areas  of  the  two  retinae.  When  this  occurs  the  two  images 
appear  as  one,  and  are  said  to  fuse.  When  the  two  images 
fall  on  non-corresponding  parts  of  the  two  retinae  the  object 
is  seen  double.  In  order  that  the  images  from  a  near  object 
may  fall  on  corresponding  parts  of  the  two  retinae  the  eyes 
must  be  so  moved  that  the  lines  of  vision  converge.  To  secure 
fusion  of  the  images  of  a  distant  object  the  eyes  must  be  so 
directed  that  their  axes  of  vision  are  almost  parallel.  (See 
Figure  4.) 

An  important  fact  is  that  vision  enables  animals  to  res- 
pond to  objects  at  a  distance. 

The  Bar.  The  external  ear  contains  a  passage  leading 
into  the  middle  ear  and  separated  from  it  by  the  tympanic 


ELEMENTS  OE  BEHAVIOR  15 


Figure  4— Diagram  showing  the  greater  convergence  required  in  fixating  near 
objects.  The  extent  of  this  convergence  is  a  cue  to  the  perception  of  distance 
and  depth. 

membrane.  When  air  vibrations  impinge  upon  this  mem- 
brane it  oscillates  back  and  forth  and  causes  movement  in  a 
series  of  three  small  bones  situated  in  the  middle  ear.  The 
movement  of  these  bones  in  turn  is  transmitted  to  the  fluid 
in  the  cochlea,  which  is  a  part  of  the  inner  ear.  Thus  vibra- 
tions are  set  up  in  this  fluid  which  have  the  same  rate  as  the 
air  vibrations  outside.  The  endings  of  a  part  of  the  auditory 
nerve  are  situated  along  the  base  of  a  row  of  rods  and  hair 
cells  which  project  into  the  fluid,  contained  in  the  cochlea. 
(See  Figures  5  and  6.)  It  is  not  certain  whether  the  auditory 
nerve  endings  are  stimulated  by  the  vibration  of  this  project- 
ing row  or  by  the  vibration  of  the  membrane  at  the  base  of 
the  row. 

The  adequate  stimuli  to  the  ear  are  vibrations  in  the 
surrounding  medium,  usually  in  the  atmosphere.  These  are 
condensation  and  rarefaction  vibrations  and  their  rate  varies 
from  something  more  than  16  per  second  to  about  50,000 
per  second.  Sound  emanates  from  a  vibrating  object  such  as 
a  bell  or  the  vocal  cords  of  an  animal  and  the  vibrations  are 
taken  up  by  the  atmosphere  and  conveyed  to  the  tympanic 
membrane.  This  enables  an  animal  to  respond  to  objects  at  a 
distance. 


16 


ELEMENTS  OF  BEHAVIOR 


oil* 


ampi 


Figure  5 — Drawing  from  a  model  of  the  inner  ear,  showing  the  cochlea,  in  which 
are  the  sense  organs  of  hearing;  the  utricle  and  saccule,  the  organs  of  static 
sense;  and  the  semicircular  canals. 


Figure  6 — Schematic  section  through  one  of  the  coils  of  the  cochlea,  showing  the 
basilar  membrane  and  the  organ  of  Corti. 

The  Nose.  In  the  wall  of  a  recess  which  opens  upon  the 
air  passages  of  the  nose  are  found  the  sense  organs  for  odor. 
The  actual  sense  organs  for  odor  are  long  nerve  cells  embedded 


ELEMENTS  OF  BEHAVIOR 


17 


between  epithelial  cells  and  with  long  processes  extending  to 
the  surface  of  the  mucous  membrane.  In  the  other  direction 
nerve  fibres  extend  from  these  cells  to  the  brain.  (See  Figure 
7.) 


Figure  7 — Section  throuyh  the  olfactory  membrane  showing  olfactory  cells  and 
supporting  cells. 

The  adequate  stimuli  to  the  olfactory  sense  organs  are 
gases  and  possibly  finely  divided  particles  in  the  atmosphere. 
These  emanate  from  objects,  especially  volatile  substances, 
and  upon  reaching  the  nose  are  inhaled  past  the  olfactory  area. 
This  makes  it  possible  for  the  animal  to  respond  to  objects  at 
a  distance,  although  the  stimulus  may  be  slow  in  reaching  the 
animal  and  gives  but  little  indication  of  the  direction  of  its 
source. 

Organs  of  Touch.  There  are  two  kinds  of  sense  organs 
for  touch.  On  parts  of  the  body  where  hair  is  absent,  such 
as  the  lips  and  the  palm  of  the  hand,  are  found  touch  corpus- 
cles which  enclose  a  core  of  cells  and  nerve  fibres.  On  the 
hairy  surfaces  the  nerve  fibres  are  found  coiled  about  the 
roots  of  the  hairs.    The  touch  corpuscles  (shown  in  Figure  8) 


end  or        nfui-onfc 
Sensory  neuron* 


Figure  8 — Touch  corpuscle  from  the  palm  of  the  human  finger,  (after  Ranvier). 


18  ELEMENTS  OF  BEHAVIOR 

are  plentiful  in  some  areas  of  the  skin  such  as  lips,  tongue, 
and  finger  tips,  and  sparsely  distributed  in  other  areas. 

The  adequate  stimulus  for  touch  is  deforming  pressure 
upon  the  skin  adjacent  to  a  corpuscle  or  to  the  "windward"  of 
a  hair,  or  pressure  upon  the  hair  itself,  which  stimulates  the 
nerve  ending  at  its  roots. 

Warmth  Organs.  The  warmth  sense  organs  are  prob- 
ably distinct  from  the  cold  sense  organs.  This  is  borne  out 
by  the  fact  that  spots  on  the  skin  sensitve  to  warmth  are  much 
fewer  than  spots  sensitive  to  cold.  There  are  on  the  average 
two  or  three  such  warmth  spots  to  the  square  centimeter  of 
skin  surface.  The  organ  is  probably  a  cylindrical  end  bulb 
found  rather  deeply  imbedded  in  the  skin. 

The  adequate  stimulus  for  warmth  is  anything  which 
increases  within  certain  limits  the  temperature  of  the  sense 
organ.  This  may  be  done  by  the  contact  of  the  skin  with 
objects  whose  temperature  is  higher  than  that  of  the  sense 
organ  at  the  time,  by  radiant  heat  emanating  from  objects  at 
a  distance,  and  by  the  dilatation  of  neighboring  blood  vessels. 
Dilatation  may  be  produced  by  the  application  to  the  skin  of 
such  substances  as  mustard  or  pepper. 

Cold  Organs.  The  sense  organs  for  cold  probably  have 
the  form  of  end  bulbs,  lying  nearer  the  surface  of  the  skin 
than  do  the  warmth  organs.  The  spots  sensitive  to  cold  aver- 
age between  10  and  15  per  square  centimeter  of  skin  surface. 

The  adequate  stimulus  for  cold  is  anything  which  reduces 
within  certain  limits  the  temperature  of  the  sense  organ.  This 
may  be  done  by  the  contact  of  the  skin  with  objects  whose 
temperature  is  lower  than  that  of  the  sense  organ  at  the  time, 
by  skin  evaporation,  by  heat  radiation  from  the  skin,  and  by 
the  constriction  of  neighboring  blood  vessels.  Certain  sub- 
stances, such  as  menthol,  stimulate  the  cold  organ  either  by 
direct  action  or  possibly  by  causing  bloodvessel  constriction.  A 
cold  spot  may  be  stimulated  by  a  pointed  hot  rod  of  a  temper- 


ELEMENTS  OF  BEHAVIOR  19 

ature  45  to  50  degrees  C.  (The  temperature  of  the  blood  is 
37  degrees  C.)    This  is  called  the  paradoxical  cold  stimulus. 

Pain  Organs.  Certain  free  nerve  endings  which  are 
found  distributed  over  most  of  the  body  surface  are  probably 
sense  organs  for  pain.  Pain  is  also  elicited  by  the  stimulation 
of  parts  of  the  body  other  than  the  skin  surface  and  possibly 
results  from  the  intense  stimulation  of  sense  organs  not  pri- 
marily concerned  with  pain. 

The  adequate  stimuli  to  the  pain  organs  are  mechanical, 
thermal,  and  chemical,  and  must  be  of  much  greater  intensity 
than  those  which  are  necessary  to  arouse  the  organs  of  touch 
and  temperature.  The  prolongation  of  these  intense  stimuli  is 
usually  injurious  to  the  animal. 

The;  Interoceptors 

Taste  Organs.  The  receptors  for  taste  are  situated  on  the 
upper  surface  and  the  margin  of  the  tongue,  a  few  occuring  on 
the  uvula,  the  epiglottis,  and  the  larynx.  They  are  in  the  form 
of  end  bulbs  penetrated  by  the  sensory  nerve  ending  and  hav- 
ing a  minute  opening  on  the  external  surface.  They  are 
grouped  together  in  certain  of  the  papillae  of  the  tongue, 
which  are  easily  observed  as  small  eminences. 

The  adequate  stimuli  for  taste  may  be  divided  into  four 
classes :  sweet,  sour,  salt,  and  bitter  substances,  and  there  are 
probably  four  corresponding  kinds  of  taste  organs.  In  order 
to  stimulate  the  organs  the  substance  must  be  soluble.  Many 
substances  such  as  peppermint,  onion,  cantaloupe,  or  cheese  are 
popularly  regarded  as  having  characteristic  tastes,  but  these 
are  for  the  most  part  odors.  When  the  nose  is  carefully 
packed,  so  that  no  respired  air  reaches  the  olfactory  surface, 
it  is  impossible  to  distinguish  clam  bouillon  from  beef  bouillon, 
black  coffee  from  quinine  solution,  honey  from  molasses,  or 
lemon  juice  from  vinegar.  These  substances  are  then  responded 
to  as  though  they  were  merely  salt,  bitter,  sweet,  or  sour. 


20  ELEMENTS  OF  BEHAVIOR 

Other  Interoceptors.  Sense  organs  are  found  throughout 
the  mucous  membrane  of  the  alimentary  tract.  Due  to  their 
isolated  position  less  is  known  concerning  their  action  than  is 
known  of  the  function  of  sense  organs  more  accessible  to  ex- 
perimentation. They  are  more  sparsely  distributed  than  are 
organs  on  the  skin  and,  though  some  respond  to  pressure  and 
temperature,  they  are  most  affected  by  chemical  stimuli. 

Their  adequate  stimuli  are  food  substances,  internal  se- 
cretions, and  the  movements  of  the  enteric  tract.  Thirst  re- 
sults from  dryness  of  the  pharynx,  and  hunger  from  a  vigor- 
ous peristaltic  movement  of  the  empty  stomach  which  occurs 
at  intervals  of  about  one  minute. 

The  Proprioceptors 

Semicircular  Canals.  These  organs,  though  not  auditory 
in  function,  are  contained  in  three  communicating  cavities  con- 
stituting a  part  of  the  inner  ear.  (See  Figure  5).  The  cavi- 
ties are,  roughly  speaking,  ringlike  in  form,  each  one  being  set 
at  right  angles  to  the  other  two.  Cells  with  hairlike  processes 
project  into  the  fluid  which  the  cavities  contain.  When  the 
head  is  rotated  in  any  plane  the  contained  fluid  in  at  least  one 
of  these  canals,  due  to  inertia,  lags  behind  the  walls  of  the 
cavity.  Because  of  this,  the  projecting  hair  processes  are  bent 
to  one  side  and  the  adjacent  nerve  fibres  are  stimulated.  This 
action  may  be  understood  by  thinking  of  a  bucket  filled  with 
water  into  which  projects  moss  which  is  attached  to  the  wooden 
surface.  When  the  bucket  is  rotated  the  water  lags  behind  and 
the  moss  is  bent.  If  the  bucket  is  kept  twirling  for  a  short  time 
the  water  takes  up  its  motion  and  continues  to  move  when  the 
bucket  is  stopped,  thus  reversing  the  direction  of  the  moss. 
The  semicircular  canals  act  in  a  similar  way,  so  that  when  a 
person  has  been  whirled  for  a  time  in  a  revolving  chair  and 
suddenly  stopped  he  responds  as  though  he  were  being  turned 
in  the  opposite  direction. 


ELEMENTS  OF  BEHAVIOR  21 

The  adequate  stimulus  to  these  sense  organs  is  rotary- 
movement  of  the  head. 

Static  Organs.  On  each  side  of  the  head  adjacent  to  the 
semicircular  canals  and  contained  in  bony  cavities  are  two 
small  membraneous  sacs,  the  utricle  and  saccule.  (See  Fig- 
ure 5).  Within  them  is  a  gelatinous  mass  into  which  project 
sensory  hair  cells.  Among  the  hairs  are  found  small  particles 
of  calcium  carbonate,  called  otoliths.  The  pressure  of  the 
otolith  weighted  mass  upon  the  hair  cells  varies  with  the  posi- 
tion and  movement  of  the  head. 

The  adequate  stimulus  to  these  organs  is  the  position  of 
the  hea'd  with  reference  to  gravity,  or  motion  of  the  head  in 
any  direction. 

Muscle  and  Tendon  Sense  Organs.  (Kinesthetic  organs) . 
In  the  muscles  are  found  sensory  "spindles"  made  up  of  modi- 
fied muscle  fibres  and  free  nerve  endings.  Similar  organs  are 
found  in  the  walls  of  bloodvessels  and  in  the  tendons. 

The  adequate  stimulus  for  these  organs  is  the  mechanical 
pressure  and  state  of  strain  in  muscles  and  tendons  which  re- 
sults from  any  bodily  movement. 

The;  Nervous  System 

A  stimulus  starts  a  chain  of  events  and  a  response  ter- 
minates it.  Between  stimulus  and  response  many  things  occur 
in  the  nervous  system. 

The  principle  has  already  been  stated  that  a  response  can 
not  result  from  a  stimulus  unless  there  is  a  pathway  of  nervous 
conduction  between  receptor  and  effector.  The  whole  nervous 
system  is  an  intricate  arrangement  of  such  pathways. 

The  brain  is  contained  in  the  skull,  and  the  spinal  cord  is 
contained  in  the  vertebral  column.  The  brain  and  spinal  cord 
constitute  the  central  nervous  system.  Sensory  nerves  lead 
from  the  sense  organs  to  the  spinal  cord  and  brain.  Motor 
nerves  leave  the  brain  and  the  spinal  cord  and  lead  to  skeletal 
muscles.  These  sensory  and  motor  nerves  constitute  the  peri- 


22  ELEMENTS  OF  BEHAVIOR 

pJieral  nervous  system.  In  addition  to  the  central  and  peri- 
pheral nervous  systems  there  is  the  autonomic  nervous  system. 
This  system  serves  the  involuntary  muscles  and  the  glands. 
The  muscles  which  it  affects  are  distinct  in  kind  from  the  skel- 
etal or  voluntary  muscles,  being  "unstriped"  in  appearance  and 
slow  in  their  action.  Through  the  autonomic  system  the  cen- 
tral nervous  system  is  connected  with  such  effectors  as  sweat 
glands,  salivary  glands,  tear  glands,  adrenal  glands,  liver, 
spleen,  stomach,  intestine,  rectum,  bladder,  genitals,  heart,  and 
blood  vessels.  The  autonomic  has  much  the  same  function  as 
the  peripheral  nervous  system.  The  relation  of  the  three  sys- 
tems may  be  seen  from  Figure  9. 


Autonomic  peripheral 


Figure  9 — Schematic  representation  of   the  relations  of  the   autonomic  and  the 
peripheral  nervous  systems  to  the  central  nervous  system. 

The  Spinal  Cord.  A  cross  section  of  the  spinal  cord 
shows  an  outer  white  area  and  an  inner  gray  area  whose  shape 
varies  at  different  levels  of  the  cord  but  preserves  a  general 
resemblance  to  the  letter  H.  (See  Figure  10).  The  outer  white 
area  is  composed  of  longitudinal  columns  of  nerve  fibres  en- 
cased in  their  white  medullary  sheaths.  The  inner  gray  area 
is  made  up  of  two  posterior  and  two  anterior  horns  with  an 


ELEMENTS  OF  BEHAVIOR 


23 


isthmus  of  connecting  or  commisural  fibres.  Its  gray  appear- 
ance is  due  to  the  presence  of  nerve  cell  bodies  lacking  the 
white  medullary  sheath  which  gives  their  color  to  the  outer 
columns. 


Ll  roof 


AnTfccior 


Figure  10 — Schematic  section  of  the  spinal  cord.  The  dotted  area  in  the  center 
is  gray,  due  to  the  presence  of  nerve  cell  bodies  and  unmedullated  fibres. 
The  outer  area  is  made  up  of  columns  of  longitudinal  fibres.  Areas  of  motor 
fibres  are  marked  M.,  and  areas  of  sensory  fibres  are  marked  S.  Other  areas 
are  mainly  connecting  fibres. 

The  Brain.  The  cerebral  hemispheres  constitute  the  larg- 
est part  of  the  human  brain.  The  cross  section  of  one  of  these 
hemispheres  shows  an  outer  layer  of  gray  matter  which  is 
called  the  cerebral  cortex.  This  is  made  up  of  un-medullated 
cell  bodies  and  nerve  fibres.  A  large  part  of  the  interior  of  the 
brain  is  seen  to  be  composed  of  white  medullated  tracts,  al- 
though there  are  distributed  in  this  area  numerous  patches  of 
gray  matter. 

Neural  Arcs.  A  sensory  or  afferent  neurone  starts  at  a 
sense  organ  and  terminates  in  the  spinal  cord.  Its  branched 
processes,  extending  upward  and  downward,  form  a  part  of 
the  sensory  columns  of  the  cord,  and  from  these  columns  its 
processes  enter  the  ventral  horn  at  various  levels.  Connecting 
neurones,  sometimes  called  association  or  internuncial  neu- 
rones, carry  impulses  from  the  sensory  systems  to  motor  sys- 
tems.   Every  neural  arc  contains  at  least  one  such  connecting 


24 


ELEMENTS  OF  BEHAVIOR 


"eurone  interposed  between  its  sensnrv  « 


OftndyiTes 


m  spinal  cord 


Figure  U-Scheaatic  represe„ta,i„n  „f  sensorv 
Fkmre  12— <?^  •  sensory  neurone. 

Schema,,  represent,™  of  molor  .^ 

-«  -rones  to  sensory  .Jj  £jj£  °f  *~  ~- 

ihe  motor  pathwav*  in  +u         •ybLems- 
sist  chiefly  of  aS ^n  "erV0US  S>'Ste'"  -» 
anterior  horn  of  the  WwT*  ^  ^  C°rtex  to  the 
Cerent  w„,o„„  lcad  t„  the  n    c  ^  ^^  h°™  motor  or 


ELEMENTS  OF  BEHAVIOR 


25 


Figure  13 — Scheme  of  motor  pathways  from  a  sense  organ  in  the  skin  to  a  muscle. 
Arrows  indicate  possible  courses  taken  by  a  nervous  impulse.  The  neurones 
are  shown  enlarged  out  of  all  proportion  to  the  size  of  the  brain  and  cord. 
(After  Starr.) 

When  an  impulse  passes  from  a  sense  organ  to  a  muscle 
by  way  of  a  sensory  neurone,  connecting  neurones  in  the  spinal 
cord,  and  a  motor  neurone,  its  pathway  is  called  a  reflex  arc. 


26  ELEMENTS  OF  BEHAVIOR 

(See  Figure  13).  Such  reflex  arcs  are  usually  instinctive 
mechanisms.  A  frog  with  its  brain  removed  responds  to  many 
stimuli  by  means  of  these  reflex  arcs. 

Regulatory  Character  of  Responses 

A  significant  characteristic  of  responses  is  that  in  general 
they  meet  successfully  the  situations  which  contribute  the 
stimuli  that  call  them  forth.  For  example,  a  foreign  object  in 
the  nose  calls  forth  a  sneeze  response  which  removes  the  irri- 
tating object.  The  visual  stimulus  of  a  fleeing  mouse  causes 
the  cat  to  make  movements  that  result  in  the  mouse's  capture, 
just  as  the  mouse,  receiving  the  visual  stimulus  of  a  cat,  is  im- 
pelled to  make  movements  of  flight.  A  baby  will  grasp  the  per- 
son who  holds  him  if  the  support  is  suddenly  released.  Stumb- 
ling results  in  extending  the  hands,  and  this  protects  the  more 
vital  parts  of  the  body  from  injury. 

A  baby  cries  when  he  is  hungry,  cold,  frightened,  or  in 
pain.  This  serves  to  bring  his  nurse  to  the  spot.  We  might 
contrast  this  mutual  regulation  in  human  beings  with  the  be- 
havior of  such  a  simple  animal  as  the  frog.  Frogs  never  come 
to  each  other's  rescue,  even  though  they  have  pain  and  danger 
calls.  The  only  call  which  summons  the  frog's  fellow  is  the 
mating  call. 

A  familiar  response  of  the  dog  is  his  scratching  reflex. 
If  stimulated  with  a  pin  point  behind  the  right  shoulder  the 
dog  makes  rapid  oscillatory  movements  with  the  right  hind 
leg,  the  utility  of  which  movement  is  obvious.  If  the  same 
stimulation  be  applied  a  short  distance  above  the  tail  at  a  spot 
which  the  scratching  foot  cannot  reach,  the  tongue  makes  re- 
flex licking  movements  even  though  the  dog  does  not  attack 
the  spot  with  his  mouth.  This  stimulation  of  any  part  of  the 
body  brings  into  play  regulatory  responses  which  usually  meet 
the  situation  appropriately. 

The  stimuli  accepted  by  the  distance  receptors  result  in 


ELEMENTS  OF  BEHAVIOR  27 

responses  which  adjust  the  animal  to  the  good  or  evil  which 
is  about  to  befall  it.  In  their  simplest  form  these  responses 
turn  the  animal  toward  or  away  from  the  stimulus,  or  increase 
or  decrease  the  distance  separating  object  and  animal. 

Decayed  Utility  or  Responses 

The  utility  of  a  response  is  often  not  evident  until  a  long 
time  after  it  is  given.  The  lapse  of  time  occuring  between  the 
response  and  the  advantage  which  the  animal  reaps  from  it 
often  makes  the  response  seem  a  matter  of  prudent  deliber- 
ation on  the  part  of  the  animal,  when  this  is  really  not  the  case. 
All  responses  of  lower  animals  are  evoked  by  present  situa- 
tions, even  when  the  future  situations  to  which  they  adjust  the 
animal  are  far  distant.  This  adjustment  to  the  future  may  in 
particular  cases  be  fruitless,  as  the  probable  event  may  never 
transpire,  but  the  response  occurs  regardless  of  this  un- 
certainty. These  probable  events  are  the  situations  in  the  en- 
vironment of  the  species  which  recur  periodically,  such  as 
night,  or  high  tide,  or  winter,  or  new  laid  eggs.  The  brooding- 
hen  does  not  forsee  the  consequences  of  her  act,  but  is  merely 
responding  to  the  eggs,  the  nest,  and  the  physiological  changes 
in  her  own  body.  The  situation  which  causes  the  squirrel  to 
store  food  in  October  is  not  the  inevitable  scarcity  of  nuts 
during  the  following  winter,  but  rather  the  surplus  food  supply 
in  the  autumn.  Some  anticipatory  reactions  of  animals  are  of 
use  only  to  others,  and  an  animal  often  dies  before  the  utility 
of  his  act  is  manifest.  A  conspicuous  example  of  this  is  the 
behavior  of  the  solitary  wasp  in  catching  and  storing  food  for 
an  offspring  whose  birth  she  does  not  ordinarily  survive. 

The  biological  utility  of  the  mating  and  nest  building  of 
birds  is  the  birth  and  shelter  of  the  offspring.  The  bird  re- 
sponds, however,  to  the  situation  at  the  time  with  as  little  re- 
gard for  the  future  as  man  has  when  he  coughs  or  sneezes  in 
response  to  foreign  objects  in  the  throat  and  nose. 


28  ELEMENTS  OF  BEHAVIOR 

Apparent  Absence  op  Utility  of  Some  Responses 

Although  we  may  usually  expect  to  find  some  use  served 
by  every  response,  there  are  many  cases  of  inappropriate  re- 
actions. For  example,  the  instinct  which  leads  a  dog  to  run 
barking  beside  the  front  wheels  of  an  automobile  seems  to 
serve  no  useful  purpose  either  to  dog  or  driver.  If  we  remem- 
ber, however,  that  the  dog  is  the  descendent  of  the  wolf  and 
that  the  wolf  in  killing  his  prey  must  depend  upon  the  pack  for 
assistance,  it  is  clear  that  there  was  a  time  when  this  reaction 
was  of  service.  By  these  movements  that  are  so  annoying  to 
us  in  the  dog,  the  single  wolf,  fleeter  than  his  fellows,  over- 
takes and  turns  back  his  prey  so  that  the  whole  pack  take  part 
in  the  killing.  The  absence  of  utility  in  the  dog's  case  is  due 
only  to  the  fact  that  he  lives  in  artificial  conditions.  Many  of 
man's  inappropriate  responses  which  are  spoken  of  as  immoral 
have  at  some  period  in  the  history  of  the  race  been  a  necessary 
means  to  his  survival. 

Living  in  a  complex  civilization  makes-  many  of  our  orig- 
inal reaction  tendencies  inappropriate.  Our  proneness  to  anger 
toward  telephone  operators,  or  toward  the  automobile  which 
resists  our  efforts  to  start  it,  is  of  no  use  to  us.  Our  natural 
equipment  does  not  include  appropriate  responses  to  these  situ- 
ations. Loudness  of  voice  and  violent  action  are  the  innate 
responses  to  situations  not  wholly  dissimilar  to  an  irritating 
operator  or  to  a  recalcitrant  machine,  so  these  are  the  re- 
sponses given  by  the  unregenerate.  When  a  man  steps  in  front 
of  us  in  the  line  waiting  for  theatre  tickets  our  adrenal  re- 
sponse, promoting  as  it  does  the  clotting  of  the  blood,  prepares 
us  for  actual  bloodshed  although  this  is  usually  needless  as  we 
may  never  come  to  blows. 

Orientation,  Locomotion,  and  Intervention 

A  response  to  stimulation  is  often  a  turning  toward  or 
away  from  certain  objects.  These  objects  are  usually  them- 
selves the  source  of  the  stimulus  which  causes  the  turning. 


ELEMENTS  OF  BEHAVIOR  29 

The  altered  position  generally  serves  one  of  two  purposes.  It 
may  put  the  animal  in  a  position  to  employ  mouth  or  legs  to 
advantage,  as  when  a  startled  animal  takes  up  an  attitude  of 
defense  or  prepares  for  flight.  It  may  change  the  direction  of 
the  animal's  sense  organs  with  reference  to  the  provoking 
stimulus  or  with  reference  to  other  stimuli  usually  associated 
with  this.  For  example  the  horse  cocks  his  ear  toward  the  un- 
usual sound,  thus  bringing  the  sense  organ  further  into  play. 
The  herd  wheel  in  the  direction  from  which  danger  may  be 
expected  in  response  to  the  danger  cry  of  the  leader.  Taking 
up  a  posture  which  permits  the  appropriate  action  of  receptors 
or  effectors,  or  which  withdraws  receptors  from  stimulation, 
is  called  orientation. 

Many  of  an  animal's  movements,  such  as  walking,  run- 
ning, jumping,  swimming,  crawling  or  flying,  serve  to  impel 
him  from  place  to  place.  Movements  which  cause  a  change  of 
location  of  the  animal  as  a  whole  are  called  locomotion. 

Responses  of  orientation  and  locomotion  frequently  occur 
simultaneously.  If  a  cow  is  standing  by  the  roadside  facing 
us  as  we  approach  in  a  vehicle,  she  merely  maintains  her  orien- 
tation with  respect  to  the  vehicle,  by  slowly  turning  her  head 
as  we  pass.  If,  on  the  other  hand,  we  approach  her  on  the 
flank  her  head  turns  toward  the  road  in  response  to  the  sound, 
but  she  is  also  actuated  to  flight.  In  order  to  keep  her  eye  on 
the  vehicle  and  at  the  same  time  to  move  forward,  she  wheels 
slowly  and  crosses  the  road  ahead  of  us.  What  seems  to  be  a 
mere  perversity  in  the  cow  is  explained  as  a  combination  of 
these  two  action  systems. 

Orientation  and  locomotion  change  the  position  of  the 
animal  with  reference  to  objects  in  the  environment,  but  do  not 
change  the  position  of  surrounding  objects  with  reference  to 
each  other.  Responses  which  serve  to  redistribute  the  parts  of 
the  outside  world  will  be  called  intervention. 

Movements  of  orientation,  locomotion  and  intervention 
all  serve  to  bring  new  stimuli  to  bear  on  the  animal  and  these  in 


30  ELEMENTS  OF  BEHAVIOR 

turn  are  succeeded  by  new  responses.  The  proportion  of  inter- 
vention responses  in  higher  animals  is  strikingly  greater  than 
in  lower  forms.  In  response  to  variations  of  season  and  food 
supply,  birds  employ  orientation  and  locomotion,  thereby  bet- 
tering their  environment.  The  hermit  crab  travels  about  until 
he  finds  a  shell  which  affords  him  shelter.  Man,  on  the  other 
hand,  by  means  of  his  elaborate  intervention  responses,  so 
constructs  the  world  about  him  as  to  lessen  his  dependence  upon 
movements  of  orientation  and  locomotion,  with  a  resulting  in- 
crease of  convenience  and  safety.  He  plants  his  crops  and 
breeds  his  cattle  instead  of  searching  for  wild  vegetables  or 
game.  He  is  born  naked  and  assumes  or  discards  clothing  ac- 
cording to  the  weather.  He  brings  together  into  one  place 
shelter,  clothing,  bed,  food,  water,  fuel,  utensils,  mate  and  off- 
spring. From  his  immediate  neighborhood  he  removes  dirt, 
enemies,  and  dangerous  objects.  He  constructs  tools  and 
weapons  which  are  of  assistance  to  him  in  further  movements 
of  intervention.  By  an  elaboration  of  mechanical  contrivances 
he  devises  vehicles  which  take  the  place  of  his  legs  in  locomo- 
tion, and  instruments  which  extend  the  range  and  accuracy 
of  his  sense  organs. 

Internal  Responses 

The  three  types  of  responses  just  mentioned,  orientation, 
locomotion  and  intervention  consist  in  movements  of  the  skel- 
etal muscles.  Animals  respond  also  by  movements  of  visceral 
muscles  and  by  glandular  secretion.6  The  dog  that  smells  ap- 
petizing food  not  only  turns  toward  the  food,  approaches  and 
tears  it  with  his  teeth,  but  also  responds  by  certain  internal  re- 
actions of  peristalsis  and  secretion.  Peristalsis  is  a  wave-like 
muscular  constriction  of  the  enteric  tract  that  serves  to  carry 
food,  once  taken  into  the  mouth,  into  stomach  and  intestines, 
and  to  knead  the  food  in  such  a  way  that  all  parts  of  it  are 
brought  into  contact  with  the  secreting  and  absorbing  walls. 

C  For    a    detailed    account   of   such    internal    responses    see    Cannon,    Bodily    Changes   in    Pain, 
Hunger,  Fear,  and  Rage. 


ELEMENTS  OF  BEHAVIOR  31 

Secretions  into  the  enteric  tract  serve  to  prepare  the  food  for 
absorbtion.  The  principal  glands  that  serve  digestion  are  in 
the  mouth,  stomach,  intestines,  pancreas  and  liver.  At  the 
sight  or  smell  of  food,  the  mouth  and  stomach  are  prepared  by 
their  secretions  to  receive  it.  The  flow  of  these  secretions  is 
later  increased  by  the  presence  of  food  in  the  mouth,  by  the 
movements  of  chewing,  and  by  the  peristalsis  of  which  swal- 
lowing is  a  part. 

When  a  cat  is  enraged  by  a  barking  dog  it  not  only  "spits" 
and  assumes  the  posture  of  defense,  but  its  peristalsis  ceases, 
and  the  bloodvessels  so  change  their  size,  by  the  play  of  minute 
muscles  in  the  vessel  walls,  that  a  greater  blood  stream  reaches 
the  fighting  and  fleeing  groups  of  skeletal  muscles.  Sugar 
stored  in  the  liver  is  liberated.  From  the  adrenal  glands  ad- 
renin  is  secreted  and  poured  into  the  blood,  with  the  result  that 
fatigue  is  counteracted  and  the  vasomotor  condition  and  ab- 
sence of  peristalsis  are  maintained.  Heart  beat  and  respiration 
show  an  appropriate  increase  of  amplitude  and  rate.  As  a  rule 
internal  responses  do  not  occur  alone,  but  accompany  move- 
ments of  orientation,  locomotion,  and  intervention.  They  fa- 
cilitate these  movements  and  in  turn  are  further  excited  by 
them. 

Emotional  expression  is  made  up  of  overt  bodily  move- 
ments and  of  characteristic  internal  responses  accompanying 
them.  The  grouping  of  responses  in  each  emotion  shows  great 
resistance  to  the  rearranging  effects  of  training,  as  is  indicated 
by  their  fundamental  similarity  in  diverse  races.  Grief,  merri- 
ment, anger,  and  love  are  expressed  in  much  the  same  way  the 
world  over.  They  are  aroused,  however,  by  varying  situa- 
tions in  different  societies.7 

When  a  person  is  stirred  to  action  by  the  internal  re- 
sponses of  rage,  fear  or  love  we  say  he  is  "moved."  This  is 
more  than  a  mere  figure  of  speech.  A  situation  which  hampers 
movement  causes  the  response  of  struggling  with  head,  body, 

7   See  Darwin,   The  Expression  of  the  Emotions  in  Man  and  in  Animals,  pages  83-115. 


32  ELEMENTS  OF  BEHAVIOR 

arms,  and  legs,  but  it  also,  either  directly  or  due  to  the  strug- 
gling, causes  certain  internal  responses  like  those  described  in 
the  case  of  the  enraged  cat.  These  internal  responses  stimu- 
late proprioceptors  in  the  viscera.  The  impulses  so  aroused 
are  conveyed  along  neural  arcs  to  the  muscles  engaged  in 
struggling,  and  their  action  is  thereby  strengthened  and  sus- 
tained. If  the  pathways  of  nervous  conduction  between  these 
proprioceptors  and  the  skeletal  muscles  should  be  severed,  this 
reenforcement  would  not  take  place  and  the  struggling  move- 
ments would  be  less  energetic  and  shorter  lived. 

The  secretion  into  the  blood  of  adrenin  from  the  adrenal 
glands  reduces  the  peristaltic  movements  in  the  intestinal  tract, 
increases  by  its  action  upon  bloodvessels  the  amount  of  blood 
in  the  skeletal  muscles,  and  by  direct  contact  makes  more  ener- 
getic the  contraction  of  the  skeletal  muscles  involved  in  the  ex- 
pression of  rage.  It  probably  promotes  clotting  of  the  blood 
which  is  of  advantage  in  case  the  ensuing  fight  results  in  the 
animal's  being  wounded. 

This  action  of  adrenin  is  another  way  of  eliciting  a  re- 
sponse. Between  the  gland  and  the  muscles  acted  upon  there 
is  no  nervous  connection.  The  blood  stream  carries  the  gland's 
secretion  to  the  muscles,  and  the  secretion  has  a  direct  chemical 
action  upon  the  muscle  tissue.  Thus  the  direct  action  of  in- 
ternal secretions  from  ductless  glands  is  complementary  to  the 
conduction  of  impulses  from  visceral  proprioceptors  through 
neural  arcs.  The  effect  of  these  secretions  is  less  prompt  than 
is  the  effect  of  neural  reenforcement,  but  persists  for  a  longer 
time. 

The  Action  of  a  Stimulus-Response  Mechanism 

Many  weak  stimuli,  which  act  upon  sense  organs  without 
causing  a  response,  will  be  found  to  call  forth  a  response  when 
the  stimuli  are  increased  in  intensity.  A  stimulus  of  an  inten- 
sity just  sufficient  to  bring  about  a  reaction  is  called  the 
threshold  stimulus  or  liminal  stimulus.  We  may  give  a  baby  a 
quinine  solution  so  weak  that  he  will  swallow  it  as  though  it 


ELEMENTS  OF  BEHAVIOR  33 

were  pure  water.  If  the  strength  of  the  solution  is  gradually 
increased,  we  reach  a  point  at  which  the  baby  will  grimace  and 
turn  his  head  away.    This  constitutes  the  threshold  point. 

If,  instead  of  increasing  in  intensity  a  stimulus  which  is 
less  intense  than  the  threshold  stimulus,  we  repeat  such  a  stim- 
ulus again  and  again,  a  response  may  be  elicited.  Bringing 
about  a  response  by  the  repetition  of  a  subliminal  stimulus  is 
called  the  summation  of  stimuli.  If,  for  example,  a  neighbor 
comes  at  night  and  knocks  on  a  man's  door  and  the  man  re- 
mains in  bed,  and  if  the  neighbor  continues  his  knocking,  the 
man  finally  rises  from  bed  and  lets  him  in,  not  because  it  is 
more  reasonable  to  do  so  now  than  it  was  before,  but  because 
of  the  neighbor's  importunity. 

The  summation  of  stimuli  is  used  extensively  in  advertis- 
ing, the  recurring  advertisment  often  leading  us  eventually  to 
buy  the  article  described.  This  accounts  in  part  for  the  num- 
ber of  people  who  use  Ivory  Soap  and  Bull  Durham.  The 
daily  sight  of  the  unanswered  letter  in  the  letter  tray  may 
finally  call  forth  a  reply.  The  ingenious  torture  which  con- 
sisted in  allowing  a  series  of  drops  of  water  to  fall  on  the 
bound  victim  produced  a  summation  effect  resulting  in  a 
greatly  increased  response. 

Within  certain  limits  the  summation  effect  is  increased  as 
the  length  of  the  intervals  between  the  subliminal  stimuli  is 
diminished.  If  the  intervals  are  lengthened  beyond  a  certain 
point  no  summation  effect  occurs. 

A  response  is  sometimes  given  only  after  a  number  of 
diverse  subliminal  stimuli  have  been  received,  and  may  be  the 
result  not  only  of  the  last  stimulus  but  of  the  entire  series. 
Bringing  about  a  response  by  a  series  of  diverse  subliminal 
stimuli  is  called  the  summation  of  diverse  stimuli.  The  pros- 
pective purchaser  of  an  automobile  is  led  to  visit  the  salesroom 
but  remains  irresolute  in  the  presence  of  the  machine.  The 
salesman  now  initiates  the  process  of  summation.  He  calls 
the  man's  attention  to  various  good  features  of  the  machine, 


34  ELEMENTS  OF  BEHAVIOR 

and  each  of  these  stimuli  brings  the  man  nearer  to  parting 
with  his  money.  The  salesman  appeals  to  his  customer's  van- 
ity by  reference  to  prominent  men  who  own  that  make  of 
machine.  Finally  a  stimulus  is  given,  such  as  the  assurance 
that  after  this  car  is  sold  none  will  be  available  for  several 
months,  and  the  purchaser  makes  out  his  check. 

To  induce  a  child  to  take  medicine,  the  summation  of 
diverse  stimuli  is  often  effective.  If  a  promise  of  candy  or  of 
money  does  not  have  results  we  may  try  such  bribery  as  offer- 
ing to  take  him  to  the  theatre,  or  we  may  threaten  to  leave  him 
at  home.  Finally,  by  petting  or  cajolery,  the  summation  is 
completed.  We  often  describe  a  person  as  being  favorably 
disposed  toward  a  certain  course  of  action.  This  usually 
means  that  he  has  already  received  the  first  few  of  a  series 
of  diverse  stimuli  and  all  that  we  need  do  is  to  complete  the 
series  in  order  to  bring  about  the  response.  For  example,  a 
man's  child  may  have  died  recently  and  we  realize  that  the 
time  is  auspicious  for  asking  him  to  contribute  to  a  children's 
charity.  The  acquaintance  whom  we  would  greet  casually  at 
home  is  welcomed  effusively  in  a  foreign  country  because  we 
are  already  stimulated  to  friendliness  by  the  internal  changes 
which  in  part  constitute  homesickness. 

The  response  to  a  series  of  stimuli  varies  according  to  the 
order  in  which  the  stimuli  occur.  A  man  standing  beside  a 
dark  road  responds  differently  to  the  sounds  of  approaching 
footsteps  and  to  the  sounds  of  retreating  footsteps,  which  may 
be  exactly  the  same  sounds  occuring  in  opposite  order.  Royce 
pointed  out  that  it  makes  a  difference  whether  a  stranger 
first  steps  on  a  man's  foot  and  then  apologizes,  or  first 
apologizes  and  then  steps  on  a  man's  foot. 

Weber's  Law 

Within  certain  limits  the  intensity  of  a  stimulus  may 
vary  without  modifying  the  nature  of  the  response.     If  the 


ELEMENTS  OF  BEHAVIOR  35 

stimulus  is  increased  or  decreased  beyond  these  limits,  the 
response  alters  its  character  or  its  energy.  The  amount  by 
which  a  stimulus  must  be  increased  or  decreased  in  intensity 
in  order  to  alter  the  response  is  called  the  differential  thres- 
hold. This  term  should  not  be  confused  with  liminal  threshold. 

About  1825  it  was  suggested  by  Weber,  a  German  inves- 
tigator, that  the  ratio  of  the  differential  threshold  to  the 
amount  of  the  stimulus  is  constant  at  all  intensities  for  each 
class  of  stimuli8.  Although  the  law  does  not  hold  for  very 
weak  or  for  very  intense  stimuli,  it  has  proven  a  demonstra- 
ble and  valuable  generalization.  The  ratio  differs  with 
different  kinds  of  stimulation,  being,  for  example,  smaller  in 
the  case  of  light  than  in  that  of  sound,  yl 

The  reflected  light  from  a  candle  introduced  into  a  sunlit 
room  may  not  be  noticed,  but  such  an  increase  of  illumination 
in  twilight  is  at  once  apparent.  It  may  be  impossible  to  dis- 
tinguish between  a  pitch  of  512  vibrations  and  one  of  513, 
but  easy  to  hear  the  difference  between  pitches  of  32  and  33 
vibrations.  A  weight  of  80  grams  and  one  of  82  grams  may 
be  reported  as  being  the  same,  but  a  weight  of  20  grams  and 
one  of  22  will  probably  be  recognized  as  different.  It  is  evident 
that  the  apparent  difference  between  two  lights  does  not 
depend  so  much  upon  the  absolute  difference  between  the 
stimuli  as  upon  the  proportion  of  this  difference  to  the  intensity 
of  the  light.  An  absolute  difference  between  two  sound 
intensities  does  not  insure  our  distinguishing  between  the  two, 
for  if  the  intensities  are  great  this  difference  may  be  inade- 
quate. The  same  is  true  of  two  weights.  In  order  that  the 
two  may  stimulate  us  to  different  responses,  it  is  necessary 
that  one  shall  be  about  three  percent  heavier  than  the  other. 
The  just  noticeable  difference  for  light  is  about  one  percent 
of  the  intensity  of  the  stimuli.  These  differential  thresholds 
vary  greatly  with  different  subjects  and  hold  only  within  a 
limited  range  of  intensities. 

8  For  a  more  detailed  account  of  Weber's  Law  see  Ladd  and  Woodworth,  Elements  of  Physio- 
logical Psychology,  pages  361ff  and  374ff. 


36  ELEMENTS  OF  BEHAVIOR 

The;  Interaction  or  Stimulus-Response;  Mechanisms 

As  no  animal  is  ever  acted  upon  by  just  one  stimulus  at  a 
time,  but  at  any  given  moment  is  exposed  to  a  great  complexity 
of  stimuli,  its  resulting  behavior  is  the  interplay  of  many  re- 
sponses. The  action  of  any  stimulus  depends  on  the  other 
stimuli  which  occur  along  with  it.  A  loud  sound  heard  on 
the  city  streets  causes  a  response  different  from  that  given  to 
the  same  sound  when  the  hearer  is  alone  in  the  woods. 

The  combination  of  all  the  stimuli  to  which  an  animal 
responds  at  any  moment  is  called  a  situation,  and  a  combina- 
tion of  responses  is  called  an  act.9 

If  the  situation  which  confronts  the  animal  tends  to 
arouse  simultaneously  two  stimulus-response  mechanisms 
there  may  occur  one  of  two  results.  One  of  the  mechanisms, 
though  not  itself  responding,  may  increase  the  tendency  of  the 
other  to  respond ;  or  one  may  interef  ere  with  the  action  of  the 
other. 

The  first  of  these  results,  where  one  system  is  an  aid  to 
the  other,  is  called  facilitation.  This  aid  or  reenforcement 
produces  a  more  lively  response  in  the  system  which  is  facili- 
tated. Suppose  a  man,  seeing  a  bear  in  the  woods,  responds 
by  a  dignified  retreat.  The  bear  now  moves  in  the  man's 
direction  and  he,  previously  walking,  breaks  into  a  run.  Pigs 
eat  more  greedily  when  other  pigs  are  sharing  the  meal,  and 
almost  any  animal  will  partake  more  rapidly  of  the  food  which 
we  threaten  to  remove.  A  toothache  ends  our  delay  in  visiting 
the  dentist,  and  a  good  appetite  makes  us  respond  promptly 
when  summoned  to  dinner. 

An  increased  tendency  to  act  is  to  be  expected  when  two 
stimuli  lead  to  the  same  response,  but  this  increased  tendency 
may  also  occur  in  cases  where  the  responses  produced  by  the 
two  stimuli  are  not  the  same. 

The  difference  between  facilitation  and  the  summation  of 
stimuli  lies  in  this,  that  the  stimuli  combined  in  summation  are 

9  These  <lofin!ttons  nre  proposed  l>y  Watson,  Psychology  from  the  Sian-dpoint  of  a  Bchayiorist, 
pages   10.    11. 


ELEMENTS  OF  BEHAVIOR  37 

all  subliminal  and  occur  serially,  whereas  the  stimuli  combined 
in  facilitation  may  or  may  not  be  subliminal  and  if  subliminal 
must  occur  simultaneously. 

Contrasted  with  facilitation  is  the  case  of  interference 
between  two  stimulus-response  mechanisms.  As  a  result  of 
interference  three  things  may  happen;  either  both  responses 
are  given  with  lessened  energy,  or  one  response  is  given 
with  lessened  energy  and  the  other  is  not  given,  or  neither 
response  occurs.  The  hampering  effect  which  one  system  has 
upon  another  is  called  distraction.  The  preventing  effect  which 
one  system  has  upon  another  is  called  inhibition.  If  a  trap  is 
baited  and  an  animal  is  led  by  the  odor  of  the  bait  to  approach 
the  trap,  and  if  there  is  no  odor  of  man  about  the  trap,  the 
animal  will  seize  the  bait  and  be  caught.  If,  however,  the 
body  odor  of  the  trapper  adheres  to  the  trap,  the  animal  will 
either  take  the  bait  less  readily  or  will  entirely  disregard  it. 
If  the  bait  is  taken  reluctantly  the  body  odor  is  a  distracting 
stimulus;  and  if  it  is  not  taken  at  all,  the  body  odor  is  an 
inhibiting  stimulus. 

The  reason  one  response  prevails  over  the  other  is  either 
that  there  is  more  resistance  in  the  conduction  path  of  one 
system  than  in  that  of  the  other,  or  that  the  relative  strength 
of  the  two  stimuli  in  terms  of  their  thresholds  is  different.10 

When  interference  so  raises  the  threshold  of  both  re- 
sponses that  neither  is  given,  we  have  mutual  inhibition.  In 
this  case  a  third  stimulus  may  bring  about  a  response  which 
removes  the  animal  from  the  first  two  stimuli,  and  the  inter- 
ference disappears.  This  may  be  seen  in  the  case  of  a  man 
who  is  addressed  by  someone  while  he  is  reading.  He  pauses 
in  his  reading  and  it  is  now  doubtful  whether  he  will  answer 
the  questioner  or  resume  his  book.  One  of  these  responses 
will  eventually  be  given  unless  a  third  stimulus,  such  as  the 
ringing  of  the  telephone,  causes  him  to  disregard  both  book 
and  questioner.  Ordinarily  man  is  acted  upon  not  by  two  but 

10  For  a  discussion  of  the  neural  basis  of  interference  see  Sherrington,  The  Integrative  Action 
of  the  Nervous  Syxtem,  pages  55,  115-149,   223. 


38  ELEMENTS  OF  BEHAVIOR 

by  a  multiplicity  of  stimuli,  and  his  rsponses  are  determined 
by  facilitating  stimuli,  inhibiting  stimuli,  distracting  stimuli, 
and  by  the  stimuli  which  primarily  elicit  the  response. 

Compromise;  Responses 

When  a  spinal  dog  is  simultaneously  stimulated  at  a  point 
on  the  shoulder  and  at  a  point  several  inches  farther  back,  he 
scratches  a  spot  somewhere  between  the  two.  His  response 
is  in  the  nature  of  a  compromise.  Man,  as  well,  when  stimu- 
lated to  two  distinct  responses  often  acts  in  a  way  which  is  a 
resultant  of  the  two  response  tendencies.  When  playing  ball 
with  a  stone  we  tend  to  throw  it  as  if  it  were  a  ball  to  the 
person  who  is  about  to  catch  it,  and  we  tend  to  refrain  from 
throwing  it  because  we  are  in  the  habit  of  not  stoning  our 
friends.  The  resultant  act  consists  in  throwing  the  rock 
gently. 

Compromise  in  emotional  responses  is  the  rule  rather 
than  the  exception.  If  a  child's  mischief  annoys  us,  we  re- 
spond to  him  both  as  to  a  child  to  be  treated  kindly  and  as  to  a 
nuisance  to  be  abated.  The  resultant  response  is  remonstrance 
with  sad  good  humor.  When  a  puppy  is  scolded  his  behavior 
is  a  compromise  between  affection  and  fear,  and  is  somewhat 
suggestive  of  the  politeness  of  human  beings  in  the  presence 
of  strangers. 


CHAPTER  2 
INSTINCT 

If  we  know  the  structure  of  a  machine  we  can  predict 
what  it  will  do  whenever  it  is  acted  upon  in  a  familiar  way. 
Man  is  no  exception  to  the  rule,  and  we  find  that  in  so  far  as 
men  are  alike  in  structure  they  respond  in  the  same  way  to 
any  event  which  affects  their  sense  organs.  Babies  all  show  a 
great  similarity  of  structure  at  birth  before  they  begin  to 
learn,  and  to  a  considerable  extent  this  similarity  of  structure 
persists  even  when  they  become  adults  and  after  each  has  taken 
on  individual  peculiarities  due  to  the  particular  influences  to 
which  he  has  been  exposed.  In  addition  to  this  partial  persis- 
tence of  the  baby's  original  nature,  there  is  a  closely  related 
fact  which  helps  to  make  all  men  somewhat  alike.  This  is 
the  fact  that  the  structures  of  all  of  us  tend  to  change  in  the 
same  way  due  to  our  growing  older.  This  change  we  call 
maturation. 

The  behavior  which  is  due  to  original  structure,  or  due 
to  the  changes  in  original  structure  which  are  the  results  of 
simple  maturation,  we  call  instinct.  Only  by  accepting  such  a 
definition  as  this  is  it  possible  to  describe  all  behavior  as  either 
instinctive  or  learned.  European  psychology  is  responsible  for 
the  uncritical  description  of  instinct  as  the  behavior  which  is 
common  to  all  men.  Although  all  men  are  fundamentally 
alike  in  their  original  structure,  there  are  individual  differ- 
ences in  instinctive  endowment,  and  this  individuality  is  no 
less  instinctive  than  commonality  or  universally  shared  traits. 
Furthermore,  a  great  deal  of  the  behavior  which  is  common 
to  all  men  is  undoubtedly  learned.  Everybody  knows  how  to 
use  a  stick  as  a  weapon,  but  no  one  does  so  instinctively.  Wear- 
ing clothing  is  as  universal  as  many  of  the  elaborate  instincts 
of  lower  animals,  but  is  of  course  a  learned  act.  The  behavior 
which  is  characteristic  of  any  particular  culture,  and  which 

(39) 


40  INSTINCTS 

is  not  found  elsewhere,  cannot  be  attributed  to  original  struc- 
ture, but  should  be  regarded  as  the  effect  of  environment. 

Classification  of  Instincts  According  to  Utilities 
We  may  classify  instincts  according  to  the  situations 
which  call  them  forth,  according  to  the  acts  involved,  according 
to  the  accompanying  emotions,  or  according  to  the  utilities  the 
instincts  serve.1  The  first  two  methods  of  classification  are 
the  most  desirable,  but  are  difficult  because  among  different 
species  a  given  situation  results  in  so  great  a  variety  of  move- 
ments and  a  given  response  may  be  elicited  by  so  great  a  var- 
iety of  situations.  A  complete  catalogue  of  responses  accord- 
ing to  situation,  or  of  situations  according  to  response,  must 
be  attempted  in  the  case  of  man,  but  this  would  be  too  detailed 
and  cumbersome  in  a  preliminary  description  of  the  instincts 
of  lower  animals.2  A  classification  according  to  the  emotions 
is  unsatisfactory  because  the  emotions  themselves  have  not  yet 
been  described  with  sufficient  exactness,  and  because  the  nature 
of  the  emotional  accompaniment  of  many  instinctive  acts  is 
obscure. 

The  uses  which  responses  serve  may  conveniently  be 
divided  into  a  few  well  recognized  classes,  and  this  division 
is  most  popular  in  listing  the  instincts  of  animals  in  general. 

The  final  or  consummatory  response  in  any  series  of 
instinctive  acts  is  always  the  basis  of  such  a  classification. 
Mating  behavior  is  always  terminated  when  copulation  occurs. 
Food-seeking  is  always  terminated  by  eating.  Nest-building 
ceases  when  the  nest  is  finished.  Flight  continues  until  a  place 
of  security  is  reached.  Combat  ends  when  the  foe  is  killed  or 
routed.  The  body  is  scratched  until  the  parasite  is  removed. 
The  behavior  which  leads  up  to  these  consummatory  responses 
varies  greatly  according  to  the  situation,  but  the  consumma- 
tory responses  themselves  are  highly  predictable. 

1  Classifications  Of  human  instincts  are  to  be  found  in  .Tamos,  Principle*  of  Psychology, 
Chapter  14;  Thorndiko,  Educational  Psychology,  Vol.  I;   MoDougall,   Social  Psychology,  Chapter  3. 

2  A  description  of  original  human  nature  in  terms  of  responses  according  to  situation  is 
undertaken  by  Xhorndike  in  Vol.  I  of  his  Educational  Psychology.  See  also  Woodworth,  Dynamic 
Psychology,  Chapter  8,    "Tho  Native  Equipment  of  Man." 


INSTINCTS 


41 


The  nest  building  of  birds  and  insects,  the  web  building 
of  spiders,  and  the  cocoon  spinning  of  larvae  are  striking 
examples  of  complicated  and  elaborate  instincts.  These  acts 
may  be  futile  if  the  normal  course  of  events  is  interfered 
with,  but  the  lower  animals  are  not  deterred  by  minor  irregu- 
larities of  situation.  Elaborate  and  serially  combined  re- 
sponses are  characteristic  of  their  instinctive  behavior.  On 
the  other  hand,  the  instinctive  acts  of  man  are  relatively 
simple,  but  in  the  process  of  learning,  these  simple  responses 
take  on  many  and  varied  combinations.  The  more  we  investi- 
gate man's  original  nature  the  less  intricate  his  instinctive 
reactions  appear  to  be.  We  ought  probably  to  regard  the 
elaborate  instincts  attributed  to  man  by  the  school  of  William 
James  as  being  for  the  most  part  learned  acts. 

Under  each  of  the  following  utilities  will  be  listed  a 
number  of  responses  to  illustrate  the  variety  of  ways  in  which 
lower  animals  adjust  themselves  to  their  needs.  Probably  few 
of  these  responses  are  purely  instinctive.  Certainly,  in  the 
case  of  man,  nearly  all  these  utilities  are  served  by  learned 
acts. 

Food 


Suckling,  together  with  head  and 

leg  movements. 
Swallowing. 

Following  while   suckling. 
Mouth  gaping  by  young  birds. 
Crying  and  whining  of  young. 
Licking. 

Disgust  rejection. 
Nursing  the  young. 
Regurgitation  by  pigeons. 
Scratching  the  ground. 
Inserting   food   into   the   mouth 

of  young. 
Clucking  by  mother  bird. 
Storing  food  for  larvae. 
Restlessness  due  to  hunger. 
Following  a  scent. 
Stalking. 
Chasing. 


Crouching. 

Lying  in  ambush. 

Springing. 

vStriking  by  snakes. 

Striking  of  fish. 

Diving  by  birds. 

Stinging  and  sucking  by  insects. 

Grasping. 

Constriction  by  snakes. 

Biting. 

Pecking. 

Tongue    movements    of    lizards 

and  frogs. 
Lapping. 
Chewing. 
Grazing. 
Rumination. 
Grit  Eating  by  birds. 
Grass  eating  by  sick  dogs. 


42 


INSTINCTS 


Creating  water  currents. 

Seizure  due  to  contact. 

Hunting  cry  of  owls  and  lions. 

Web  building. 

Carrying  home  food. 

Food  storing. 

Migration. 


Fighting  and  intimidating  pos- 
sible competitors. 

Threatening  wing  movements  of 
pigeons  while  eating. 

Hunting  in  packs. 

Ants  guiding  fellows  to  source 
of  food. 


Reproduction 


Preliminary  restlessness. 
Mating  calls. 
Drumming  by  partridge. 
Odoriferous  secretions. 
Strutting,      showing     off, 

dancing. 
Coyness  of  females. 
Fighting  among  males. 
Nuptial  flight  of  some  insects 


Migration. 

Consummation  of  courtship. 

Polygamous     and     polyandrous 

grouping, 
and  Affectionate     behavior     toward 

permanent  mate. 
Laying  eggs. 
Setting. 
Care  of  eggs. 


Shelter 


Restlessness  in  the  open. 

Stereotropisms. 

Seeking  temporary  concealment. 

Retirement  to  shelter  in  response 

to  darkness. 
Symbiosis. 
Permanent   residence    in    caves, 

rock  shelters,  hollow  trees. 
Seeking  shelter  high  above  the 

ground. 
Orientation  toward  entrance  of 

habitation. 
Burrowing  and  excavating. 
Cocoon  spinning  and  the  use  of 

secretions  in  building. 
Caterpillar's    use    of    leaves    in 

building. 


Collecting  building  materials 
such  as  mud,  sticks,  leaves, 
hair. 

Rearranging  these  into  nests  and 
dens,  in  trees,  on  ground,  in 
burrows. 

Plucking  fur  and  down  from 
breast  for  lining  nest. 

Dam  building  by  beavers. 

Yarding  of  moose. 

Huddling  of  cattle. 

Laying  eggs  in  foreign  nest  by 
cuckoo. 

Cooperative  nest  building  of  in- 
sects. 


Defense 


Restlessness  when  alone  and 
seeking  company  of  fellows, 
resulting  in  herds  and  colon- 
ies. 

Secretions  of  cuttlefish,  skunk, 
etc. 

Discharge  of  nematocysts. 

Taking  up  posture  which  makes 


the  animal  seem  more  formi- 
dable. 

Snarling,  growling,  screaming 
(often  in  defense  of  food). 

Cries  which  summon  aid. 

Responding  to  cries  for  aid. 

Groaning. 

Immobility. 


INSTINCTS 


43 


Frogs'  ceasing  to  croak  on  ap- 
proach of  intruder. 

Flight  (often  to  place  inacces- 
sible to  pursuer). 

Concealment. 

Withdrawal  m  o.v  e  m  e  n  t  s  of 
snails,  bivalves,  turtles,  etc. 

Flexion  of  porcupine. 

Defensive  grouping  of  herd. 

Attack  with  bill. 

Fighting  with  wings. 

Residual  fighting  movements  of 
pigeons  while  eating  which 
serve  to  threaten  opponents. 

Cry  of  warning  to  fellows. 

Clinging  of  young. 

Resisting   forcible  manipulation. 


Struggling,  squirming,  biting 
when  held. 

Clinging  to  object  when  aggres- 
sor attempts  to  take  it  away. 

Fawning,  placating  and  ingratia- 
ting behavior. 

Mother  bird's  attracting  atten- 
tion from  nest. 

Retaliatory  aggression. 

Leaning  away  from  heights  and 
clinging. 

Withdrawal  from  water. 

Attack  directed  toward  obstacles 
and  confining  objects. 

Flight  from  odors  of  natural 
enemies. 

Cat's  finding  new  nest  for  kit- 
tens that  are  often  disturbed. 


Cleanliness 


Licking  the  bodv. 

Dusting  plumage. 

Preening. 

Scratching. 

Biting  parasites. 

Shaking  of  wet  paw  by  kittens. 


Picking  off  foreign  objects  from 

surface  of  body. 
Cleaning  of  eggs  by  ants. 
Rolling 
Shaking 

Avoiding  putrid  matter. 
Scratching  dirt  over  filth. 


Careful  observation  of  animals  will  disclose  the  fact  that 
practically  none  of  the  items  in  the  above  list  refers  to  an  act 
which  is  always  executed  in  the  same  way.  An  act  of  flight, 
for  example,  is  never  twice  the  same.  The  movements  depend 
upon  the  contour  of  the  ground,  upon  the  position  of  the  ene- 
my, and  upon  previously  formed  habits  of  all  sorts.  Such 
"instincts"  as  these  are  nothing  more  than  the  continuance  of 
behavior  of  many  sorts  until  a  consummatory  response  has 
been  given.  A  frightened  partridge  uses  many  means  of 
escape,  struggling,  running,  or  flying,  until  the  consummatory 
response  of  reaching  concealment  terminates  its  activity. 

Greater  uniformity  in  the  order  of  the  parts  of  an  elabor- 
ate "instinct"  is  seen  when  each  component  act  changes  the 
situation  in  a  set  and  characteristic  way.     Nest-building  is  a 


44  INSTINCTS 

case  in  point.  A  shelf  under  the  eaves  is  a  stimulus  which  may 
start  a  mated  bird  in  its  search  for  building  materials.  Its 
return  to  this  spot  with  material  in  its  mouth  initiates  laying 
the  foundation  of  the  nest.  Its  empty  bill  starts  it  off  again  on 
a  search  for  more  materials.  Return  is  delayed  until  its  mouth 
is  again  filled.  Its  second  nest-building  movement  is  deter- 
mined by  finding  the  nest  already  begun,  and  so  each  step  in  the 
building  is  governed  by  the  degree  of  completion  of  the  nest  at 
the  time.  This  may  be  demonstrated  by  partially  demolishing 
a  nest  which  has  been  almost  completed.  The  bird  will  act 
then  much  as  it  did  when  the  nest  first  reached  this  stage  of 
completion. 

To  call  pugnacity,  or  constructiveness,  or  acquisitiveness, 
or  self-preservation,  or  mating,  an  instinct  is  a  dangerous  con- 
cession to  popular  usage.  Each  component  act  as  elicited  by  a 
particular  situation  might  better  be  so  called,  always  bearing  in 
mind  that  this  series  of  acts  is  terminated  by  a  consummatory 
response.  A  complete  understanding  of  behavior  always  in- 
volves an  analysis  in  terms  of  stimulus-response  mechanisms, 
and  to  name,  for  example,  all  the  behavior  of  carnivorous  ani- 
mals which  results  in  securing  food  "the"  hunting  instinct 
serves  little  purpose  but  to  end  prematurely  the  student's  sci- 
entific curiosity.  If  we  rest  content  with  the  description  of 
the  hunting  instinct  as  the  unlearned  behavior  of  a  carnivorous 
animal  which  results  in  his  securing  food,  we  certainly  add 
nothing  to  anyone's  information  when  we  say  that  animals 
secure  food  by  means  of  the  hunting  instinct.  Such  an  expla- 
nation is  of  the  sort  given  byMoliere's  physician  when  he  says 
that  opium  puts  one  to  sleep  because  it  possesses  a  soporific 
property.  It  we  are  going  to  make  use  of  "instinct"  in  the  de- 
scription of  behavior,  the  terms  must  apply  to  specific  reaction 
tendencies. 

In  civilization  man  has  wrought  so  many  changes  in  his 
habitat  and  established  so  many  rules  and  conventions,  that  the 
primitive  world  for  which  he  was  originally  adapted  has  in 


INSTINCTS  45 

many  cases  ceased  to  exist.  On  account  of  this  we  find 
many  maladjustments  of  man  toward  his  present  environment. 
Lying,  stealing,  murder,  and  discourtesy  all  have  their  basis 
in  original  human  nature,  and  the  theologians  are  quite  right 
in  their  dogma  of  original  sin. 

Although  some  of  man's  original  responses  occasion  mal- 
adjustment in  an  artificial  culture,  others  are  appropriate  to 
both  savagery  and  civilization,  and  still  others  may  in  civiliza- 
tion be  put  to  new  uses.  This  is  true  in  the  domestication  of 
animals  as  well  as  in  the  socialization  of  men.  When  the  hunt- 
ing dog  leaves  canine  and  enters  human  society,  his  old  trick 
of  turning  back  the  quarry  to  the  pursuing  pack  is  taken  ad- 
vantage of  by  his  master  and  serves  a  new  purpose.  The  same 
is  true  of  retrieving,  which  can  be  taught  only  to  a  dog  that  al- 
ready possesses  the  retrieving  mechanism. 

Man  first  shows  generosity  and  kindliness  in  general  to 
his  family  group  because  his  early  childhood  is  spent  at  home. 
The  attachment  of  these  response  tendencies  to  the  father, 
mother,  brother,  sister — situation  makes  it  useful  to  employ 
family  names  to  elicit  these  friendly  responses  toward  society 
when  the  child  becomes  an  adult  and  leaves  his  home.  Hence 
we  have  the  terms  "brother  man",  "brother  Elk",  "little  brown 
brother",  "less  fortunate  sister",  "sister  republic",  "mother 
church",  "the  greatest  mother  of  all",  "mother  country", 
"fatherland",  "city  fathers",  "father  of  his  country",  and 
many  others.  Because  the  husband-wife  relationship  does  not 
exist  for  the  child,  these  terms  do  not  elicit  responses  of  the 
sort  just  mentioned,  and  are  not  found  to  have  this  derived 
meaning  in  popular  speech.  The  foregoing  is  more  an  analogy 
than  an  illustration  of  the  way  in  which  original  responses  may 
be  put  to  new  uses,  as  the  child's  responses  to  the  family  are 
actually  learned,  but  learned  in  early  infancy  and  in  situations 
which  are  common  to  all  men.  These  responses  are  therefore 
practically  as  universal  as  original  reaction  tendencies. 

No  matter  how  much  man  modifies  his  conditions  of  life, 


46  INSTINCTS 

the  human  nature  of  babies  remains  the  same ;  and  though  man 
may  build  up  elaborate  machinery  of  law  and  custom  for  con- 
trolling his  natural  tendencies,  in  the  race  these  original  ten- 
dencies remain  the  constant  and  fundamental  determiners  of 
behavior,  while  conventional  restrictions  differ  with  time  and 
place. 

There  is  no  evidence  for  the  common  supposition  that  the 
neurological  habits  of  parents  are  passed  on  to  their  children 
in  the  form  of  instincts.  There  are,  however,  many  experi- 
mental results  which  demonstrate  conclusively  that  certain 
of  the  parents'  acquired  characteristics  are  inherited  by  the 
offspring.  All  these  inherited  bodily  modifications,  such  as 
congenital  syphilis  or  transmitted  malnutrition,  are  of  a  sort 
quite  distinct  from  the  neurological  changes  involved  in  habit 
formation,  and  offer  no  evidence  for  the  belief  that  education 
is  inherited.  Children  descended  from  generations  of  Eng- 
lish-speaking ancestors  are  probably  no  quicker  in  learning 
English  than  are  babies  of  foreign  extraction. 

Individual  Differences 

Everyone  recognizes  the  fact  that  in  a  group  of  horses 
or  cows  or  chickens  one  individual  differs  from  another.  Some 
horses  are  naturally  faster,  and  some  are  naturally  slower. 
One  cow  is  a  good  milker  and  another  cow  gives  but  little 
milk,  even  though  both  have  had  the  same  care  and  feeding. 
Chickens  vary  in  size  and  in  the  number  of  eggs  they  will  lay. 
Even  in  the  case  of  men  we  recognize  differences  in  height  and 
in  pigmentation  which  are  due  to  endowment  and  not  to  nature. 

It  is  a  tendency  of  our  own  times  to  be  less  willing  to 
admit  that  from  birth  one  man  differs  from  another  in  intel- 
lectual ability.  To  a  very  great  extent,  however,  we  are  born 
and  not  made.  Some  men  are  gifted  with  brains,  and  some 
are  handicapped  by  a  natural  inferiority  for  which  no  amount 
of  training  will  compensate.    The  great  majority  of  people  in 


INSTINCTS 


47 


the  world  could  never  graduate  from  college,  because  of  their 
inadequate  intellectual  endowment. 

There  are  very  few  college  students  who  can  run  the  hun- 
dred yards  in  10  seconds,  more  who  can  do  it  in  11,  still  more 
who  can  do  it  in  12,  and  probably  about  an  equal  number  who 
can  do  it  in  13.  From  this  point  on  we  find  fewer  and  fewer 
students  whose  fastest  time  is  14,  15,  16,  or  more  seconds. 
If  an  unselected  group  of  students  were  to  start  together  to 
run  the  length  of  a  football  field,  they  would  be  strung  out  at 
the  finish  in  some  such  way  as  shown  in  Figure  14. 

-#      "*    *  **  T*&S%$&-*^i  J; 

n  sec  7 "TT-       *•*■*•£.         *■      +*Z. 


n  sec 
ma,v\ 


it  sec. 
men 


13  sec.     \%  sec. 
wen       men 


li  sec. 

men 


iosec. 

ma 


Figure  14 — 


Their  distribution  according  to  speed   might   be   repre- 
sented graphically  as  in  Figure  15. 


/ 

/ 

\ 

X-  * 

\ 

Figure   15 — Surface   of    frequency   showing   the   distribution    of   the    runners   of 
Figure  14  according  to  their  time  in  seconds. 


It  is  possible  by  the  use  of  mental  tests  to  measure  with 
but  slight  error  the  amount  of  a  man's  innate  intellectual 
ability,  and  to  compare  the  amount  of  this  natural  endowment 
with  that  of  people  in  general.  If  we  were  to  give  our  group 
of  students  mental  tests,  we  would  find  a  few  of  them  to  be 
conspicuously  bright,  more  of  them  to  be  a  little  less  intelligent, 
a  great  many  of  them  bunched  about  the  point  of  average 
performance,  and  fewer  and  fewer  at  points  lower  and  lower 


48 


INSTINCTS 


in  the  scale.     Such  a  measurement  of  the  intelligence  of  stu- 
dents is  represented  in  the  following  graph : 


Score  m  Alpha  test 


Figure  16 — Distribution  of  scores  of  2010  students  at  the  University  of  Wash- 
ington in  the  army  intelligence  test  Alpha. 


In  general,  bright  parents  have  bright  children,  mediocre 
parents  have  mediocre  children,  and  dull  parents  have  dull 
children.  Striking  exceptions  to  this  rule  should  not  be  given 
undue  weight.  The  handicap  of  ill  health,  poverty,  or  lack 
of  educational  opportunity,  or  the  advantage  of  excellent 
training  have  some  effect  upon  the  score  which  an  individual 
makes  in  intelligence  tests.  This  effect,  however,  is  relatively 
slight. 


CHAPTER  3 
LEARNING 

Although  all  babies  start  life  with  much  the  same  capaci- 
ties, we  find  them  as  adults  displaying  various  individual 
abilities  which  have  been  gained  through  practice  and  educa- 
tion. They  have  become  judges,  farmers,  carpenters,  editors, 
burglars,  and  politicians.  Each  has  developed  skill  along  cer- 
tain lines  .  Psychology  must  explain  how  these  diverse  habits 
are  developed. 

We  seldom  observe  in  adults  an  elaborate  act  which  is  a 
pure  instinct,  and  this  is  because  the  original  structure  of  the 
nervous  system  changes  as  a  result  of  use.  We  must  not, 
however,  fall  into  the  error  of  supposing  that  when  any 
response  is  modified  by  learning,  it  thereupon  ceases  to  be 
instinctive.  The  instinctive  components  of  any  act  may  be  dis- 
cerned, no  matter  how  greatly  it  has  been  transformed  by 
training. 

The  modifications  of  instinctive  behavior  which  result 
from  use  are  of  two  sorts.  A  response  may  be  aroused  by  a 
stimulus  which  did  not  originally  provoke  it,  and  the  degree  of 
ease  with  which  any  response  is  elicited  may  be  altered.  As  a 
consequence  of  these  changes,  we  may  have  a  collection  of 
instinctive  movements  fused  together  into  what  is  called  a 
habit.  We  shall  first  consider  the  modifications  in  the  ease 
with  which  responses  are  brought  about,  and  later,  under  the 
heading  "The  Conditioned  Response",  we  shall  discuss  the 
attachment  of  responses  to  new  stimuli. 

Positive  Adaptation 

Repeated  working  of  a  stimulus-response  mechanism, 
especially  if  the  stimulus  is  just  above  the  threshold  of  re- 
sponse, results  in  lowering  the  threshold,  in  decreasing  the 

(49) 


50  LEARNING 

reaction  time,  and  in  increasing  the  energy  with  which  the 
response  is  given.  This  effect  of  repeated  working  is  called 
positive  adaptation. 

Because  of  practice,  the  lookout  on  board  ship  is  able  to 
signal  the  approach  of  a  vessel  more  readily  than  is  the  lands- 
man who  stands  beside  him.  If  the  situation  is  such  that  we 
always  get  up  when  the  alarm  clock  rings,  the  clock  may  be 
moved  farther  and  farther  from  the  bed  on  successive  nights 
until  we  are  finally  aroused  by  a  sound  much  too  faint  to  have 
gotten  us  out  of  bed  on  the  first  morning.  A  physician  may 
develop  a  positive  adaptation  to  the  telephone  at  night,  while 
his  wife  sleeps  through  the  disturbance.  His  wife,  on  the 
other  hand,  is  often  the  only  one  who  responds  to  the  crying 
of  the  baby.  The  suburbanite  develops  a  sensitive  ear  to  the 
whistle  of  the  early  train;  the  bank  teller  is  quick  to  detect 
counterfeit  money;  the  woodsman  notices  signs  which  escape 
the  city  dweller;  and  all  of  us  turn  when  a  dime  is  dropped 
even  on  a  noisy  street.  If  we  were  to  see  two  signboards  side 
by  side  and  lettered  in  the  same  type,  one  bearing  the  words 
BULL  DURHAM  and  the  other  the  nonsense  words  RAHD 
LULBUM,  and  if  these  were  just  near  enough  to  enable  us 
to  read  the  first  of  these  signs,  we  would  not  be  able  to  decipher 
the  second,  though  the  same  letters  occur  on  the  two  signs. 
We  do  not  develop  positive  adaptation  to  all  stimuli  that  act 
upon  sense  organs,  but  only  to  those  that  provoke  a  response. 

When  we  first  learn  to  perform  an  act  in  response  to  a 
new  stimulus,  the  time  involved  in  giving  the  response  is  much 
longer  than  it  is  at  a  later  period,  after  practice.  This  short- 
ening of  reaction  time  is  best  studied  where  a  large  number 
of  stimuli  are  responded  to  in  novel  ways,  as  in  learning  to 
typewrite,  to  send  or  receive  telegraphic  messages,  to  translate 
a  foreign  text,  or  to  take  dictation  in  shorthand.  By  measuring 
the  performance  of  any  of  these  acts  during  successive  prac- 
tice periods,  and  by  plotting  these  measurements,  we  get  what 
is  called  a  practice  curve. 


LEARNING  51 

In  telegraphy  the  practice  curve  for  either  sending  or  re- 
ceiving shows  that  more  and  more  words  may  be  handled  in 
a  given  time  as  practice  continues.  There  is,  of  course,  a  limit 
to  such  improvement,  and  the  telegrapher  finally  approximates 
his  maximum  speed.  As  this  limit  is  approached  the  curve 
flattens  out.  Thus  the  first  part  of  practice  is  relatively  more 
fruitful  than  the  last  part.1 

Through  use,  the  tendency  of  a  response  to  follow  its 
stimulus  becomes  better  established.  This  greater  tendency 
to  sequence  is  shown  not  only  in  a  lowered  threshold  and  a 
shortened  reaction  time,  but  in  an  increased  resistance  to  dis- 
traction. The  practiced  act  is  performed  in  the  face  of  altered 
conditions  and  in  spite  of  internal  variations  which  would  orig- 
inally have  prevented  the  reaction. 

Positive  adaptation  is  gradually  lost  after  practice  has 
been  discontinued.  This  slow  disappearance  of  positive  adap- 
tation is  called  forgetting,  and  may  be  measured  just  as  the 
appearance  of  positive  adaptation  may  be  measured.  The  rate 
of  forgetting  as  graphically  represented  is  at  first  rapid.  As 
time  passes,  the  loss  of  practice  effects  takes  place  at  a  slower 
rate,  and  even  after  years  of  disuse,  a  stimulus-response  mech- 
anism may  still  show  traces  of  positive  adaptation. 

Anyone  who  has  narrowly  escaped  being  struck  by  light- 
ning shows  a  greater  fear  response  than  before  to  the  distant 
thunder  storm.  If  we  have  been  provoked  to  anger  by  another's 
outrageous  act,  he  may  arouse  our  anger  again  by  the  most 
trivial  discourtesy.  This  might  at  first  seem  to  be  evidence 
that  positive  adaptation  results  best  from  reponses  to  intense 
stimuli  but  this  is  probably  not  so. 

It  requires  a  very  intense  stimulus  to  call  out  an  extensive, 
diffuse,  and  complete  emotional  response,  although  parts  of 
the  response  may  be  given  to  a  weak  stimulus.  Once  the  re- 
sponse has  been  called  out  in  its  entirety,  the  elements  origin- 

1  Thomdike,  Notes  on  Practice,  Improvability,  and  the  Curve  of  Work,  Amer.  Jour.  Psychol., 
1916,  pages  550-565.  Hill,  Rejall,  and  Thorndike,  Practice  in  the  Case  of  Typewriting,  Ped. 
Sem.,   1813,   pages  516-529.     Lashley,    The  Acquisition  of  Skill  in  Archery,  Carnegie  Inst.,   1915. 


52  LEARNING 

ally  having  high  thresholds  are  more  easily  elicited  and  the 
act  as  a  whole  is  bound  together  by  what  we  shall  later  call 
conditioning.  This  explains  why  a  child  who  has  been  thor- 
oughly frightened  shows  cowardice  on  slight  provocation.  His 
entire  fear  mechanism  has  been  called  into  action  and  the 
partial  fear  response,  which  is  ordinarily  given  by  children 
who  have  never  known  abject  fear,  gives  place  to  a  more  com- 
plete expression  upon  insignificant  occasion.  The  child  who 
has  often  been  teased  to  a  point  of  rage,  shows  positive  adapta- 
tion of  those  parts  of  the  rage  response  which  are  naturally 
more  difficult  to  elicit,  and  thus  develops  a  bad  temper  toward 
small  grievances. 

Negative;  Adaption 

If  a  subliminal  stimulus  is  repeated  with  gradually  in- 
creasing intensity,  the  response  may  not  occur  when  the  stim- 
ulus reaches  or  even  passes  the  usual  threshold  point,  and  in 
this  way,  especially  if  the  response  is  never  given,  the  thres- 
hold of  response  may  be  permanently  raised.  This  is  called 
negative  adaptation. 

If  the  temperature  of  the  room  falls  gradually  we  fail 
to  notice  it,  but  if  for  any  reason  it  suddenly  becomes  cold  we 
react  to  the  change.  If  the  cost  of  living  were  to  double  over- 
night there  would  be  public  disorder  the  next  day,  but,  because 
the  doubling  is  a  gradual  process  occupying  several  years,  the 
situation  remains  below  the  threshold  for  rioting.  The  physic- 
ian is  inured  to  the  suffering  of  others  by  witnessing  it  repeat- 
edly, and  by  the  necessary  inhibition  of  any  useless  expression 
of  sympathy.  A  child  who  is  afraid  to  sleep  without  a  light 
may  become  adapted  to  sleeping  in  entire  darkness  by  a  grad- 
ual reduction  of  the  intensity  of  the  light  on  successive  nights. 
The  practised  person  while  using  a  microscope,  shows  negative 
adaptation  for  stimuli  affecting  his  left  eye.  The  disobedient 
child  is  indifferent  to  his  parent's  call  because  he  has  failed 
to  respond  on  many  occasions.    In  order  to  train  a  dog  to  come 


LEARNING  53 

when  called,  the  expert  dog  trainer  never  uses  the  dog's  name 
except  in  summoning  him.  The  visitor  in  a  household  is  dis- 
turbed by  the  children's  noise,  while  the  parents  may  have 
become  adapted  to  it.  Many  parents  also  become  negatively 
adapted  to  their  children's  questions  and  are  surprised  when 
their  attention  is  called  to  this. 

James  thought  it  unfortunate  that  man  is  endowed  with 
a  fear  response,  the  severity  of  which  often  renders  him  help- 
less in  the  face  of  danger.2  Nearly  anyone,  if  he  were  com- 
pelled to  walk  an  I-beam  high  above  the  street,  would  be  seized 
by  panic  and  would  fall.  But  James  overlooked  the  fact  that 
this  original  over-supply  of  fear  is  of  value  when  it  is  ulti- 
mately decreased  by  negative  adaptation  to  the  dangerous 
situation.  If  fear  were  not  found  in  excess  in  the  ingenuous 
man,  the  danger-adapted  man  would  often  die  of  foolhardi- 
ness.  Excessive  embarrassment  handicaps  the  adolescent  in 
the  presence  of  strangers,  but  we  all  dislike  the  adult  in  whom 
negative  adaptation  has  been  so  thoroughgoing  as  to  leave  no 
traces  of  reticence. 

A  man  is  saved  from  feeling  distaste  for  his  ageing  wife 
because  wives  grow  old  gradually,  and  he  becomes  negatively 
adapted  to  characteristics  which,  were  they  to  occur  suddenly, 
would  discourage  his  affection.  The  proper  way  to  break  a 
horse  to  the  saddle  is  to  accustom  him  first  to  a  blanket,  next 
to  blanket  and  surcingle,  then  to  the  saddle  in  addition.  Later, 
to  adapt  him  to  the  pressure  of  the  rider,  a  bag  of  feed  of 
gradually  increased  weight  may  be  strapped  across  the  saddle. 
Successful  breaking  depends  upon  keeping  the  stimuli  within 
the  horse's  growing  toleration.  A  disliked  food  taken  in  quan- 
tities sufficiently  small  to  excite  no  disgust,  may  be  eaten  in 
gradually  increasing  amounts  on  successive  occasions  until  a 
large  portion  does  not  cause  aversion.  Crowding  the  thres- 
hold for  intolerance  of  a  stimulus,  without  reaching  the  break- 
ing point,  makes  for  increased  tolerance. 

2  James,  Principles  of  Psychology,  Vol.  2,   page  419. 


54  LEARNING 

Another  way  in  which  negative  adaptation  may  result  is 
by  the  failure  of  the  response,  though  given,  to  rid  the  animal 
of  the  stimulus.  In  such  a  case,  the  stimulus-response 
mechanism  becomes  fatigued,  and  the  response  is  given  less 
and  less  energetically  to  the  persistent  stimulus,  until  all 
response  ceases.  The  horse  which  is  broken  by  the  cow- 
puncher  method  becomes  accustomed  to  the  saddle  when  his 
efforts  to  dislodge  it  repeatedly  fail,  and  so,  while  he  may 
always  make  slight  movements  of  resistance  while  being 
saddled,  the  threshold  of  resistance  is  permanently  raised. 

We  have  said  that  negative  adaptation  may  be  brought 
about  in  two  ways.  The  repetion  of  a  subliminal  stimulus  may 
cause  it ;  or  it  may  result  when  a  stimulus  persists  in  spite  of 
the  animal's  responses,  after  fatigue  has  raised  the  threshold. 
There  is  a  third  kind  of  situation  which  results  in  negative 
adaptation.  An  eliciting  stimulus  may  be  rendered  ineffective 
by  the  presence  of  an  inhibiting  stimulus,  and,  the  threshold 
of  response  being  thus  raised,  negative  adaptation  results.  In 
this  way  children  become  negatively  adapted  to  temptingly 
accessible  food  by  the  inhibiting  threat  of  punishment.  In 
Triplett's  experiments,  perch  were  separated  from  minnows, 
which  are  their  natural  food,  by  a  glass  partition  in  the 
aquarium.  Aperch  would  at  first  dart  toward  a  minnow,  but 
would  strike  its  head  against  the  glass.  In  time  the  big  fish 
became  negatively  adapted  to  the  presence  of  the  minnows. 
The  partition  was  then  removed  and  the  minnows  mixed  safely 
with  their  natural  enemies.  This  case,  though  an  example  of 
negative  adaptation,  involves  habit  formation  and  this  will  be 
discussed  below.3 

Both  negative  adaptation  and  summation  follow  upon  the 
repetition  of  subliminal  stimuli,  though  they  are  quite  different 
results  of  such  repetition.  It  is  the  length  of  the  intervals 
between  the  stimuli  that  determines  which  one  of  these  two 
effects  will  occur.    A   series  which  will   have   a   summation 

3  Triplett,   The  Educability  of  the  Perch,  Amer.   Jour.  Psychol.,  Vol.   12,   page  354. 


LEARNING  55 

effect,  and  finally  bring  about  a  response,  may  lose  that  effect 
if  the  length  of  the  intervals  between  stimuli  is  increased,  in 
which  case  negative  adaptation,  or  the  permanent  raising  of 
the  threshold,  takes  place.  These  alternative  possibilities  are 
seen  not  only  in  behavior  but  in  the  physiological  responses  of 
the  body  to  drugs.  If  one  dose  rapidly  follows  another,  a  cu- 
mulative effect  results,  but  if  gradually  increasing  doses  are 
given  at  widely  separated  intervals,  negative  adaptation, 
results,  so  that  the  patient  may  come  to  tolerate  amounts  of 
the  drug  which  would  have  been  fatal  at  the  outset. 

Transitory  Changes  or  Threshold  During  a  Single  Practice 

Period 

If  a  considerable  time  has  passed  since  an  act  was  last 
performed,  the  threshold  of  response  is  found  to  be  unusually 
high  and  the  reaction  time  to  be  unusually  long.  When  a  ball 
player  begins  his  day's  practice  he  is  less  sensitive  to  situations 
and  slower  to  respond  than  he  is  after  fifteen-  minutes  of 
warming  up.  In  golf  we  take  a  few  practice  strokes  before 
driving  from  the  first  tee  in  order  to  pass  this  period  of  slug- 
gish reaction.  The  slowness  and  the  weakness  of  response  and 
the  high  threshold  that  characterize  the  beginning  of  any 
activity  we  shall  call  initial  torpor.4 

Initial  torpor  is  seen  in  simplest  form  in  the  contractility 
of  the  muscle-nerve  preparation  or  in  a  spinal  reflex.  When 
it  is  exhibited  in  such  a  complex  act  as  game  playing  or  factory 
work,  other  elements  enter  in  to  make  it  appear  greater  than  it 
really  is.  When  work  has  first  begun,  negative  adaptation  to 
distraction  has  not  yet  occurred.  Passers-by,  noises,  and 
room  temperature,  all  disturb  us  at  first,  but  later,  through 
negative  adaptation,  are  disregarded. 

Another  obscuring  factor  is  the  hangover  of  responses 
recently  given.  Conversation  just  engaged  in  leaves  the  talker 
for  some  time  afterward  still  talking  to  himself.  If  we  turn 
from  chess  to  letter  writing,  a  tendency  to  make  chess  moves 

4  Thorndike,    Educational   Psychology,   Vol.    2. 


56  LEARNING 

hampers  the  composition  of  our  first  paragraph.  The  student 
who  has  hurried  to  avoid  being  late  at  class  is  agitated  for 
some  time  after  taking  his  seat.  This  hangover  of  recent 
movements  is  due  partly  to  the  persistence  of  emotional  re- 
cnforcement. 

A  complex  habit  is  made  up  of  many  parts  and  involves 
many  action  systems.  Initial  torpor  attaches  to  each  part 
and  to  each  emotional  reenforcement.  It  is  dissipated  in  the 
parts  of  lowest  threshold  before  it  disappears  in  others.  As 
one  part  after  another  of  the  entire  act  is  brought  into  play 
by  tentative  beginnings,  and  by  the  stimuli  which  these  begin- 
nings bring  to  bear  upon  us,  the  several  parts  of  the  act  suc- 
cessively lose  their  sluggishness  and  combine  into  the  act  as  a 
whole.  After  such  warming  up  the  entire  habit  has  a  lowered 
threshold. 

Every  time  work  is  begun  after  a  long  period  of  rest, 
initial  torpor  is  found  to  be  present.  If  the  practice  curve  is 
still  rising  and  has  not  reached  a  plateau,  the  absolute  amount 
of  initial  torpor  to  be  overcome  is  less  at  the  beginning  of  each 
successive  practice  period.  There  is  no  difference  in  kind 
between  the  positive  adaptation  shown  in  overcoming  initial 
torpor  and  the  positive  adaptation  which  is  the  gradually 
decreased  reaction  time  and  lowered  threshold  of  an  act  prac- 
ticed at  intervals  for  many  days  and  graphically  represented 
by  the  practice  curve  as  a  whole. 

Toward  the  end  of  the  doubleheader  the  ball  player  again 
becomes  less  sensitive  to  situations  and  slower  in  response,  and 
this  we  call  fatigue.  Toward  the  end  of  the  shift  in  the  factory 
the  number  of  accidents  increases.5  The  third  time  around 
the  links  we  make  a  poor  score.  Fatigue  is  the  slowness  of 
response,  the  weakness  of  response,  and  the  high  threshold  of 
response  which  finally  occur  if  any  activity  is  continued  long 
and  vigorously.  It  is  a  temporary  effect  of  repeated  action, 
and  a  period  of  rest  causes  it  to  vanish.8 

5  Uoldmark,   Fatigue  and  Efficiency,  Russell   Sage  Foundation,    1912,    page   71. 

6  Thorndike,  Fatigue  in  a  Complex  Function,  Psychol.  Rev.,   1914,  pages  402-407. 


LEARNING 


57 


Figure  17— Distribution  of  German  industrial  accidents  throughout  the  working 
day,  showing  fatigue.     (After  Goldmark). 


The  Conditioned  Response 

How  may  a  response  be  provoked  by  a  new  stimulus  ?  Let 
us  take  the  case  of  a  dog  that  sees  a  cat.  On  seeing  the  cat 
he  barks.  Suppose  that  while  looking  at  the  cat  he  hears  his 
master  say  the  word  "cats",  and  that  these  two  stimuli  occur 
together  several  times.  Later  if  he  hears  the  word  "cats", 
although  there  is  no  cat  present,  he  will  bark.  This  response 
originally  called  forth  by  the  sight  of  a  cat  is  now  provoked  by 
a  new  stimulus,  namely,  the  sound  of  a  word.  When  a  response 
is  elicited  by  a  new  stimulus,  due  to  the  fact  that  the  new 


58  LEARNING 

stimulus  has  occurred  along  with  the  old,  it  is  called  a  condi- 
tioned response. 

If  a  percussion  hammer  falls  upon  the  patellar  tendon, 
a  spinal  reflex  is  elicited  involving  the  contraction  of  the  quad- 
riceps muscle.  This  is  called  the  knee-jerk.  In  1902,  Twitmyer 
demonstrated  that  if  a  bell  was  sounded  each  time  that  a  ham- 
mer fell  on  the  patellar  tendon,  it  was  possible,  after  consider- 
able practice  had  occurred,  to  elicit  the  knee-jerk  by  the  audi- 
tory stimulus  alone.7  Today  a  reflex  response  to  a  substituted 
stimulus  is  called  a  conditioned  reflex,  because  the  substituted 
stimulus  is  always  one  of  the  conditions  accompanying  the 
original  stimulus.  Pavlow  discovered  that  a  conditioned  sal- 
ivary reflex  could  be  secured  from  dogs.  Certain  foods,  when 
eaten,  cause  a  copious  secretion  of  the  salivary  glands.  He 
found  that,  if  some  visual  or  auditory  stimulus  is  made  the 
invariable  accompaniment  of  the  saliva-exciting  food,  the 
accompanying  condition  will  provoke  the  salivary  flow  in  the 
absence  of  the  original  food  stimulus.  Watson  and  Lashley 
demonstrated  the  conditioned  salivary  reflex  in  man  as  well 
as  other  conditioned  reflexes  in  both  dogs  and  human  beings.8 

The  principle  that  one  of  the  accompanying  conditions  of 
a  stimulus  responded  to  may  later  become  a  substituted  stim- 
ulus for  the  response,  applies  to  all  associative  learning.  If 
a  bell  is  attached  to  a  dog's  tail  and  the  dog  is  petted  in  a  way 
to  make  him  wag  his  tail,  the  sound  of  the  bell  will  be  a  con- 
stant condition  under  which  the  caudal  response  is  elicited. 
After  considerable  wagging  of  the  belled  tail  the  bell  may  be 
removed  and  the  wagging  produced  without  petting  when  the 
dog  hears  the  bell  rung.  In  order  to  make  a  dog  respond  to 
his  name  when  called,  the  trainer  secures  this  response  first 
to  food  and  then,  while  the  dog  is  coming,  speaks  his  name.  In 
time  the  sound  of  the  name  becomes  the  substituted  stimulus 
for  approach. 

7  Twitmyer,   .4   Study  of  the  Knee  Jerk,  Phila.,   1902. 

8  Watson,   Psychology,   pages   29-38. 


LEARNING  59 

If  a  number  of  photographs  are  presented  to  a  subject, 
each  one  being  named  by  the  experimenter  and  then  by  the 
subject  as  he  looks  at  the  photograph,  a  conditioned  response 
will  in  time  be  established  toward  each  picture,  so  that  the 
subject  will  call  it  by  the  proper  name.  The  previous  stimulus 
for  this  response  was  the  word  spoken  by  the  experimenter, 
and  the  substituted  stimulus  is  the  accompanying  visual  repre- 
sentation. In  like  manner  probably  any  response  may  be  con- 
ditioned by  accompanying  stimuli  in  the  absence  of  the  original 
stimulus.  Nausea  may  occur  at  the  mere  sight  or  odor  of 
food  in  which  a  nauseating  medicine  was  once  taken  or  which 
was  eaten  during  a  storm  at  sea.  This  fact  was  made  use  of 
in  curing  the  whiskey  habit.  Mark  Tvvain  found  it  difficult 
to  speak  on  serious  matters  in  public  because  he  himself  con- 
stituted a  conditioning  stimulus  which  always  provoked 
laughter  in  his  audience.8 

Conditioned  Emotional  Responses 
An  interesting  example  of  a  conditioned  response  is  seen 
in  the  attachment  of  an  emotional  expression  to  some  situation 
which  originally  had  no  power  to  bring  out  the  emotion.  Pro- 
bably each  emotion  is  originally  provoked  by  a  very  limited 
number  of  situations.  Tickling  is  the  adequate  stimulus  for 
causing  the  baby  to  smile,  but  the  baby  may  learn  to  smile  at 
sight  of  the  person  who  has  tickled  him  because  he  has  been 
exposed  simultaneously  to  the  tickling  and  to  the  sight  of  the 
tickler.  He  is  not  originally  afraid  of  the  sight  of  a  dog  and 
indeed  will  ordinarily  reach  toward  it,  but  once  frightened  by 
its  bark  or  knocked  down  by  its  rush  the  subsequent  sight  of 
the  dog  is  sufficient  to  cause  the  expression  of  fear.10  The  dog 
once  kicked  by  the  milkman  will  fly  into  a  rage  at  sight  of  him, 
his  rage  response  being  originally  provoked  by  the  kick,  but 
conditioned  by  the  appearance  of  the  man. 

9  Interesting   examples    of    conditioned    emotional    responses    are    described    by    Locke    in    his 
Ettap  Concerning  Human  Understanding,  Book  2,   Chapter  33. 

10  An  experiment  in  establishing  conditioned   emotional   responses  in   an  infant  is  described  by 
Watson  and  Rayner,   Conditioned  Emotional  Reactions,  Jour.   Exper.   Psychol.,    1920,    pages  1-14. 


60  LEARNING 

It  is  in  this  way  that  we  learn  to  show  anger,  joy,  fear, 
love,  disgust,  and  other  emotions  in  response  to  those  occur- 
rences of  life  which  are  apt  to  be  followed  by  events  that  make 
these  responses  appropriate.  Thus  we  anticipate  the  attack 
of  a  familiar  foe,  or  by  an  early  withdrawal  avoid  too  close 
contact  with  the  frightful  object.  Many  of  our  fears,  likes, 
or  dislikes  are  conditioned  responses  to  stimuli  which  have 
only  a  chance  temporal  connection  with  their  natural  provoca- 
tion. A  celluloid  collar  in  itself  is  neither  alluring  nor  repul- 
sive, and  our  dislike  of  such  an  article  of  dress  is  dependent 
upon  the  fact  that  we  have  always  experienced  it  in  connection 
with  a  wearer  who  is  not  too  scrupulous  as  to  his  personal 
cleanliness.  Everyone  builds  up  a  set  of  emotional  tendencies 
through  this  process  of  association,  so  that  his  adult  attitude 
toward  the  experiences  of  life  is  fitted  to  the  culture  into  which 
he  has  been  born. 

Particular  melodies  become  associated  with  the  words  of 
songs  and  with  emotional  expressions  which  have  been  called 
out  by  these  words.  Although  at  first  only  the  words  may 
have  had  the  power  to  arouse  the  emotions  in  question,  the 
music  itself,  in  the  absence  of  the  words,  will  later  have  the 
same  effect.  Easter  and  Christmas  music,  the  melody  to 
which  sentimental  words  were  sung,  patriotic  airs,  the  words 
of  which  originally  excited  patriotic  emotions,  or  the  music 
sung  at  the  funeral  of  a  friend,  will  long  afterward  revive  the 
emotional  expression  of  which  they  were  at  first  the  incidental 
accompaniment.  Conversely,  music  itself  may  directly  arouse 
emotional  responses,  and  this  fact  is  made  use  of  to  reenforce 
the  conviction  which  the  attending  words  but  partly  establish. 
The  stirring  airs  of  the  camp  meeting  or  the  patriotic  rally 
bring  many  to  the  mourner's  bench  or  the  recruiting  office 
who  would  remain  sinners  or  slackers  if  appealed  to  by  words 
alone. 

Emotional  expressions  as  a  whole  may  be  attached  to 
new  stimuli  and  in  inappropriate  situations  constitute  many  of 


LEARNING  61 

the  psychoneuroses.  If  in  the  process  of  courtship  a  person 
is  placed  in  a  position  to  arouse  great  fear,  the  emotion  of  fear 
may  become  attached  to  all  erotic  stimuli,  and  what  is  known 
as  an  anxiety  neurosis  may  develop.  Cases  have  been  reported 
in  which  an  aversion  for  small  rooms  can  be  attributed  to  the 
subject's  having  fainted  at  one  time  in  a  small  close  room ;  in 
which  a  fear  of  buzzing  insects  followed  a  child's  being 
frightened  by  a  humming  bird  which  entered  a  window  and 
flew  rapidly  about  the  child's  head ;  in  which  a  horror  of  bells 
was  caused  by  a  church  bell's  ringing  at  the  same  time  that 
great  depression,  resulting  from  her  mother's  death,  possessed 
the  subject,  who  believed  herself  responsible  for  her  mother's 
illness.  Such  conditions  often  call  for  treatment  at  the  hands 
of  a  psychologist. 

The  way  in  which  these  bad  habits  of  emotional  response 
are  cured  is  to  attach  a  rival  response  to  the  stimulus  which 
arouses  them.  If,  for  example,  a  person  shows  a  morbid  aver- 
sion towards  touching  absorbent  cotton,  the  psychoanalyst  at- 
tempts to  discover  the  origin  of  this  response  by  delving  into 
the  subject's  past.  It  may  be  found  that  as  a  child  the  subject 
once  handled  some  dirty  cotton  which  had  been  used  as  a  sur- 
gical dressing,  and  that  he  was  at  that  time  scolded  by  a  dis- 
gusted parent.  For  practical  purposes  it  probably  does  not 
matter  whether  this  event  was  the  original  occasion  for  the 
subject's  distaste  for  cotton,  provided  the  subject  is  himself 
convinced  that  this  was  the  real  cause.  With  this  start,  the 
psychoanalyst  proceeds  to  lower  the  threshold  for  the  recol- 
lection of  this  childhood  event,  and  so  makes  certain  that  the 
subject  will  always  think  of  the  event  when  cotton  is  seen. 
The  subject  is  then  told  that  little  children  can  not  be  held 
responsible  for  failure  to  avoid  unsanitary  acts,  that  the  sub- 
ject himself  was  in  no  way  to  be  blamed  for  what  he  did,  that 
certainly  no  harm  resulted  from  his  act,  and  that,  indeed,  the 
whole  matter  is  very  ludicrous  as  we  look  back  upon  it. 


62  LEARNING 

In  this  way  there  becomes  attached  to  the  sight  of  cotton 
the  tendency  to  discuss  the  childhood  event  and  for  such  dis- 
cussion to  be  accompanied  by  self-satisfaction  and  amusement. 
If  this  line  of  response  is  sufficiently  practised  and  sufficiently 
reenforced  by  verbal  rationalization,  it  develops  a  threshold 
which  is  lower  than  that  of  the  aversion  response,  and  thus  the 
aversion  habit  is  cured. 

An  act  may  be  learned  in  response  to  one  situation  and 
later  given  to  another  which  is  partially  identical,  even  though 
the  common  elements  in  the  two  situations  are  wholly  inci- 
dental and  irrelevent.  This  substitution  does  not  involve  the 
process  of  conditioning.  It  is  nicely  illustrated  by  many  false 
moves  in  everyday  life.  The  following  cases  have  been  re- 
cently observed.  A  person  was  about  to  make  tea.  Instead  of 
turning  on  the  gas  for  the  bunsen  burner,  lighting  it  with  a 
match,  turning  on  the  water  faucet,  filling  the  kettle,  and  plac- 
ing the  kettle  over  the  burner,  he  made  the  mistake  of  turning 
on  the  water,  lighting  the  match,  and  placing  the  match  under 
the  faucet.  The  mistake  was,  of  course,  due  to  the  similarity 
of  proprioceptive  stimulation  involved  in  turning  the  gas  cock 
and  opening  the  water  faucet,  t\ie  false  response  being  practi- 
cally the  same  as  the  gas-lighting  response.  Another  example 
of  the  substitution  of  one  stimulus  for  another,  due  to  partial 
identity,  was  found  in  the  case  of  a  man  who  entered  a  shop 
to  purchase  a  newspaper  and  who  dropped  his  money  on  the 
floor.  He  picked  up  the  money  and  left  the  shop  without  secur- 
ing the  paper,  and  did  not  appreciate  his  mistake  until  he  was 
some  distance  away.  Here  the  responses  of  picking  up  the 
coin  and  of  picking  up  the  newspaper  are  almost  identical,  and 
the  mere  act  of  picking  something  up  was  the  usual  stimulus 
for  leaving  the  shop. 

Facilitating  Effect  or  Conditioning  Stimuli 

If  a  dog  that  has  been  trained  to  respond  to  the  word 
"cats"  sees  a  cat  at  such  a  distance  that  the  stimulus  is  below 


LEARNING  63 

the  threshold  for  chasing,  his  master  may  urge  him  on  by- 
using  the  word  and  he  may  at  once  start  in  pursuit.  In  this 
way  the  sound  of  the  word  "cats",  although  not  now  the  sole 
cause  of  the  response,  facilitates  the  response,  because  it  occurs 
in  conjunction  with  the  actuating  stimulus. 

Illustrations  of  these  conditioning  stimuli  and  their  re- 
sulting facilitation  are  plentiful  in  everyday  life.  The  literary 
man  accustomed  to  writing  while  smoking  a  pipe  finds  it  dif- 
ficult to  work  without  the  pipe  in  his  mouth.  The  person 
habituated  to  evening  clothes  dines  with  greater  ease  when 
correctly  dressed.  The  clergyman  is  moved  to  greater  elo- 
quence when  wearing  his  cassock,  and  would  find  it  difficult 
to  preach  a  sermon  on  the  street  corner.  The  college  instructor, 
because  he  frequently  uses  chalk  during  lectures,  finds  facili- 
tation to  his  speech  through  holding  a  piece  of  chalk  in  his 
hand.  Our  familiar  surroundings  increase  our  personal  effic- 
iency, and  this  law  gives  a  psychological  justification  to  the 
so  called  right  of  personal  property. 

A  man  sleeps  best  in  his  own  bed,  not  only  because  he  is 
negatively  adapted  to  the  distracting  stimuli  of  his  neighbor- 
hood, but  because  he  has  gone  to  sleep  many  times  in  these 
surroundings  and  they  have  a  facilitating  effect  in  producing 
slumber.  A  child  often  refuses  to  sleep  unless  covered  by  a 
familiar  blanket,  or  allowed  to  suck  his  thumb,  or  permitted 
to  take  a  certain  doll  to  bed  with  him. 

Neurae  Basis  of  the  Conditioned  Response 

Conditioned  responses  involve  the  formation  of  new 
pathways  and  the  possibility  for  this  is  best  afforded  by  the 
intricate  association  fibres  of  the  cortex.  When  a  neural  arc 
is  acting,  impulses  received  from  sense  organs  not  previously 
connected  with  this  neural  arc  are  likely  to  be  drained  into  its 
outgoing  motor  pathway.  This  drainage  establishes  new  syn- 
apses and  thus  connects  new  sense  organs  with  the  responding 


64 


LEARNING 


muscle.    This  is  the  neural  basis  of  the  conditioned  response. 
This  may  be  best  understood  by  consulting  the  diagram  in 


Figure  18. 


MujtltJ 


Figure  18 — Establishing  a  conditioned  response.  The  first  stimulus  which  sets  the 
dog  to  running  and  barking  is  the  sight  of  the  cat.  If,  at  the  same  time, 
he  is  stimulated  by  the  word  "cats"  pronounced  by  his  master,  the  impulses 
resulting  are  drained  into  the  system  which  is  acting,  and  a  pathway  is 
established.  After  practice,  this  sound  becomes  the  conditioning  stimulus 
which  may  set  the  dog  into  activity  in  the  absence  of  any  cat. 


LEARNING  65 

Impulses  aroused  by  accompanying  conditioning  stimuli 
re  drained  into  the  motor  system  which  is  active  at  the  time, 
"hus  when  the  original  stimulus  and  the  conditioning  stimulus 
ct  together  the  combined  energy  from  the  two  is  drained  into 
single  motor  system.  For  this  reason  the  conditioing  stimu- 
xs  facilitates  the  action  of  the  original  mechanism  and  this 
lay  act  with  less  intense  stimulation  than  was  first  required. 

The  Serial  Response 

Each  movement  a  man  makes  is  likely  to  bring  him  into 
ew  relations  with  his  surroundings  and  thus  cause  new  stim- 
li  to  act  upon  him.  In  this  way  a  stimulus  produces  a  re- 
ponse,  this  response  a  new  stimulus,  this  stimulus  a  new 
esponse,  and  so  on  until  the  man  reaches  a  place  where  there 
re  no  more  stimuli  which  cause  movement.  If  such  a  series 
>  repeated  many  times  the  man's  responses  show  positive 
daptation  to  each  of  the  several  stimuli,  so  that  the  time 
equired  for  going  through  the  series  of  responses  is  short- 
ned.  Entering  our  own  house  is  an  act  which  we  all  perform 
moothly  and  quickly.  The  first  time  we  entered  the  house, 
owever,  we  were  less  quick  in  opening  the  gate  and  in  closing 
after  us,  slower  in  mounting  the  unfamiliar  steps,  finding  the 
ey,  and  unlocking  the  front  door.  As  we  repeat  the  act  day 
fter  day  bur  entrance  takes  less  and  less  time.  This  increase 
1  speed  is  in  part  a  simple  positive  adaptation  of  response  to 
le  successive  stimuli  of  gate,  steps,  key,  and  lock. 

In  addition  to  the  stimuli  which  affect  our  eyes  and  to 
■hich  our  responses  are  given,  there  is  another  series  of  stim- 
li  which  the  responses  themselves  cause  and  which  accom- 
any  the  visual  stimuli.  These  are  stimuli  to  the  propriocep- 
:>rs  in  the  muscles  and  tendons  caused  by  the  movements  of 
lanipulation  and  walking,  and  the  stimuli  to  the  end  organs 
f  touch  which  these  movements  occasion.  These  movement- 
roduced  stimuli  play  a  role  similar  to  that  of  all  other  stimuli 
-hich  are  incidental  to  the  actuating  stimulus,  in  that  they 

-3 


66  LEARNING 

serve  to  condition  the  response  when  the  actuating  stimulus 
is  absent,  or  to  facilitate  the  response  when  the  yoccur  time 
after  time  along  with  the  actuating  stimulus.  This  facilitation 
is  a  cause  for  the  increased  speed  of  the  serial  reaction  in 
addition  to  the  positive  adaptation  mentioned  above. 

In  the  same  way  a  person  learns  his  way  about  the  house, 
at  first  depending  upon  his  eyes  to  avoid  obstacles  and  to  find 
the  easiest  route  from  place  to  place  As  all  movements  are 
accompanied  by  proprioceptive  stimulation,  in  time  he  is  able 
to  dispense  with  visual  stimuli  and  to  find  his  way  about  in 
the  dark.  Tying  a  cravat  or  lacing  a  shoe  is  at  first  dependent 
upon  visual  stimuli,  but  later  each  component  movement  be- 
comes almost  wholly  conditioned  by  the  kinaesthetic  and  touch 
stimuli  occasioned  by  the  preceding  movement.  A  pianist  while 
learning  a  musical  composition  depends  upon  his  score  as  a 
guide  in  making  each  movement.  Later,  because  each  move- 
ment becomes  the  cue  to  the  next,  due  to  its  stimulation  of 
sense  organs  in  the  muscles,  and  due  to  its  producing  sounds 
which  stimulate  the  ear,  the  'musician  may  throw  away  his 
score.  If  a  printed  page  is  read  aloud  many  times  the  book 
may  be  closed  and  the  passage  spoken  from  memory.  This  is 
in  part  the  result  of  the  sound  of  each  word  becoming  the  con- 
ditioning stimulus  for  the  movements  producing  the  next 
word,  and  in  part  the  result  of  the  accompanying  kinaesthetic 
stimulation  playing  a  similar  role.  In  learning  to  write  we 
first  depend  upon  copy  books,  but  later,  in  addition  to  the 
conditioning  proprioceptive  stimulation,  the  sight  of  the  first 
letter  of  the  familiar  word  which  the  pen  forms  becomes  a 
conditioning  stimulus  for  writing  the  second  letter  and  this  is 
a  conditioning  stimulus  for  the  third  and  so  on.11 

When  a  person  is  learning  to  dance  he  makes  one  move- 
ment after  another  in  response  to  each  verbal  direction  of  his 
instructor.  While  one  movement  is  being  made  the  instructor 
gives  directions  for  the  next,  so  a  proprioceptive  stimulation 

11  On   the   neutral    basis    of   chain    reflexes    and   serial    responses    see   Herrick,    Introduction    to 
Neurology,  and  Sherrington,   Integrative  Action  of  the  Nervous  System,  page  181ff. 


LEARNING 


67 


C  V"  c 

'igure  19 — Diagrammatic  representation  of  the  chain  reflex  mechanism  (after 
Herrick).  C,  synapses  in  nerve  centers.  E,  effectors.  R,  receptors.  The 
action  of  each  effector  results  in  the  stimulation  of  an  adjacent  receptor. 
The  stimulation  of  each  receptor  results  in  the  action  of  an  effector. 

:aused  by  the  preceding  movement  accompanies  the  instruc- 
or's  verbal  stimulus.  With  repetition  of  the  stimulus-re- 
sponse series,  these  proprioceptive  stimuli  become  condition- 
ng  stimuli  and  serve  to  link  together  the  responses  in  the 
ibsence  of  verbal  direction.  When  this  dependence  of  each 
novement  upon  the  muscle  stimulation  of  the  preceding  move- 
nent  occurs,  we  say  the  person  has  learned  to  dance.  The  way 
n  which  this  substitution  of  movement-produced  stimuli  for 
he  original  exteroceptive  stimuli  comes  about  is  illustrated  in 
"igure  20. 

The    facilitating   effect   of    accompanying   conditioning 
stimuli  is  seen  in  what  might  appear  at  first  sight  to  be  cases 

I  Receptors 


Muscles  and 
Proprioceptors 

'-IJL 

'igure  20 — Diagrammatic  representation  of  the  formation  of  a  serial-response 
habit.  (After  Dunlap).  The  series  of  responses  is  at  first  the  result  of  the 
successive  stimulation  of  the  distance  receptors  shown  at  the  top  of  the  figure. 
During  practice  this  stimulation  is  accompanied  by  the  stimulation  of  pro- 
prioceptors in  the  acting  muscles.  This  proprioceptive  stimulation  gives  rise 
to  nervous  impulses  which  are  drained  as  indicated  by  the  arrows  into  the 
acting  system  and  in  time  the  series  of  responses  may  be  elicited  by  these 
movement-produced  stimuli,  only  the  first  of  the  distance  receptor  stimuli 
being  necessary. 


68  LEARNING 

of  simple  positive  adaptation.  Thus  positive  adaptation  to  the 
alarm  clock  is  shown  by  the  conscientious  person  who,  always 
responding,  is  eventually  stimulated  to  rise  by  the  faintest 
tinkle.  He  is  aided  in  rising,  however,  by  the  fact  that  his 
first  start  of  surprise  has  been  followed  by  the  movement  of 
his  arm  in  throwing  off  the  covers,  and  this  in  turn  by  sitting 
up,  feeling  for  his  slippers,  putting  them  on,  and  rising  to  his 
feet.  When  this  series  of  movements  is  made,  the  propriocep- 
tive stimuli  occur  in  a  certain  order  and  become  conditioning 
stimuli  which  serve  to  fix  the  sequence  of  responses.  Positive 
adaptation  plays  its  part  in  speeding  up  each  step  in  the  chain 
reaction,  but  the  most  important  factor  in  maintaining  the 
response  as  a  whole  is  the  series  of  conditioning  propriocep- 
tive stimuli. 

Such  conditioning  stimuli  as  are  mentioned  above  are  in- 
volved in  the  movements  themselves,  and  are  not  subject  to  the 
vagaries  of  the  external  environment,  Hence  they  serve  to 
stereotype  the  response  as  a  whole  in  a  way  which  would  not 
be  possible  if  the  organism  had  to  depend  for  guidance  wholly 
on  external  situations  whose  regular  occurrence  is  uncertain. 
These  orderly  response  series,  now  partly  independent  of  the 
environment,  constitute  most  of  our  skilled  acts  and  enable 
man  with  his  aptitude  for  such  habit  formation  to  dispense 
with  the  fixed  instinctive  order  of  responses  characteristic  of 
the  behavior  of  the  lower  animals.  This  is  not  because  man 
has  more  proprioceptors  or  other  sense  organs  than  have  lower 
animals,  but  because  in  man  these  sense  organs  have  more 
extensive  connections  in  the  central  nervous  system.  The  re- 
sulting plasticity  enables  man  to  adjust  himself  to  various 
cultures,  occupations  and  environments. 

The  Effects  of  Practice  on  the  Serial  Response 

The  effects  of  practice  in  establishing  a  serial  response 
have  been  measured  by  Ebbinghaus,  who  determined  the  num- 
ber of  repetitions  necessary  for  learning  a  series  of  nonsense 


LEARNING 


69 


yllables  so  that  it  might  be  reproduced  once  without  error.  By 
i  nonsense  syllable  is  meant  such  a  sound  combination  as  nis, 
;-eg,  fof,  gol,  nen,  kev,  and  so  forth.12 

The  longer  the  series,  the  greater  is  the  number  of  repe- 
itions  required  for  learning.  Ebbinghaus  could  repeat  a  se- 
ies  of  seven  syllables  after  having  said  it  once,  whereas  a 
eries  of  12  syllables  required  about  16  repetitions,  a  series 
>f  16  syllables  required  30  repetitions,  one  of  24  syllables, 
4  repetitions,  and  one  of  36  syllables,  55  repetitions.  These 
.re  represented  in  Figure  21. 


L£NGTH  OF  SERIES 


igure  21 — The  number  of  repetitions  required  for  establishing  serial  responses 
of  various  lengths.  The  material  learned  consisted  of  series  of  nonsense 
syllables.  A  repetition  consists  of  saying  any  series  once,  irrespective  of  the 
length  of  the  series.  The  syllables  were  spoken  at  the  rate  of  150  a  minute. 
(After  Ebbinghaus). 


12  See:     Lyon,    Memory    and    the    Learning   Process;    Meumann,    Psychology    of    Learning;   and 
bhinghaus,    Memory. 


70 


LEARNING 


These  results  may  be  stated  in  another  way,  namely,  ir 
terms  of  the  actual  amount  of  work  done  to  learn  each  series 
Repeating  12  syllables  16.6  times  involves  pronouncing  19< 
syllables;  repeating  16  syllables  30  times  involves  pronounc 
ing  480  syllables ;  repeating  24  syllables  44  times  involves  pro 
nouncing  1056  syllables;  and  repeating  36  syllables  55  time: 
involves  pronouncing  1980  syllables.     If  we  plot  these  value: 


L  '!■  V     !!V'j 


DM  uiijmu 


Figure  22 — The  same  results  are  shown  as  in  Figure  21,  but  are  represented  ii 
terms  of  the  actual  amount  of  work  done  in  order  to  learn  the  series  o 
various  lengths.  Except  for  series  of  less  than  12  syllables,  the  work  re 
quired  is  a  linear  function  of  the  length  of  the  series. 


LEARNING  71 

•aphically  we  find  they  lie  approximately  on  a  straight  line, 
figure  22). 

This  means  that  as  we  pass  from  one  series  to  another, 
e  difference  in  the  work  required  for  learning  is  proportional 
the  difference  in  the  lengths  of  the  series  learned.  If  the  syl- 
bles  are  repeated  at  intervals  of  .4  sec,  or  in  other  constant 
lythm,  the  time  consumed  will  be  proportional  to  the  number 
syllables  spoken.  If  we  prepare  series  of  nonsense  syl- 
bles  of  totally  different  material  and  of  different  lengths, 
•ntaining  16,  17,  18,  19,  etc.,  syllables  respectively,  and  find 
at  16  syllables  are  learned  in  3  minutes  and  17  in  3^2  min- 
es, then  the  series  of  18  syllables  will  be  learned  in  4  min- 
es, the  series  of  19  syllables  in  AVz  minutes,  the  series  of 
)  in  5  minutes,  and  so  on.  It  will  then  take  13  minutes  to  learn 
series  of  36  syllables. 

Even  though  it  may  be  impossible  to  remember  tomorrow 
hat  we  have  learned  today,  today's  learning  makes  tomor- 
iw's  relearning  easier.  The  amount  of  positive  adaptation  re- 
aining  from  previous  practice  may  be  measured  by  the  num- 
:r  of  repetitions  saved  when  material  is  learned  over  again, 
his  method  of  measuring  retention  has  become  known  as  the 
ving  method. 

Ebbinghaus,  using  a  number  of  different  16  syllable  se- 
ss,  repeated  some  8  times,  some  16,  some  24,  some  32,  some 
I,  some  53,  and  some  64  times.  Twenty  four  hours  after  each 
ie  was  practiced  he  found  the  number  of  repetitions  neces- 
ry  for  relearning  it.  In  this  way  he  discovered  that  each  one 
'  any  number  of  repetitions  produced  the  same  amount  of  re- 
ntion  as  any  other.  It  happened  that,  for  the  length  of  series 
led,  each  of  the  original  repetitions  saved  the  next  day  one 
:rcent  of  the  time  that  would  have  been  required  if  there  had 
:en  no  previous  practice.  Thus  8  repetitions  saved  8.1  percent 
:  the  next  day's  work,  32  repetitions  saved  32  percent  of  the 
:xt  day's  work,  and  53  repetitions  saved  53.9  percent.  The 
.tigue  resulting  from  many  repetitions  made  it  impossible  to 
.rry  the  experiment  beyond  the  point  of  64  repetitions.  Ex- 


72 


LEARNING 


cept  for  this,  100  repetitions  would  probably  have  made  it  pos- 
sible to  reproduce  the  series  the  next  day  without  any  review. 
It  will  be  remembered  that  to  learn  a  series  of  16  syllables,  so 
that  it  may  be  repeated  once  without  error  immediately  after 
the  learning,  requires  about  30  repetitions.  Figure  23  shows 
the  relation  between  the  first  day's  practice  and  the  next  day's 
relearning. 

Forgetting 

If  a  given  amount  of  material  is  memorized,  we  may 
measure  the  amount  retained  in  memory  at  any  later  time  by 
finding  the  length  of  time  which  is  required  to  relearn  the  ma- 


NUMBER 


* 


*EPETlf?ONS 


48 


Figure  23 — The  time  saved  in  relearning  a  serial  response  of  16  nonsense  syllables 
shown  as  a  function  of  the  amount  of  yesterday's  practice.  The  amount  of 
positive  adaptation  found  at  the  time  of  relearning  is  a  linear  function  of  the 
amount  of  work  done  24  hours  earlier.     (After  Ebbinghaus). 


LEARNING  73 

terial.  The  time  saved  in  relearning,  compared  with  the  time 
required  for  the  original  learning,  gives  us  a  quotient  which 
stands  for  the  proportion  retained  in  memory.  By  this  method 
it  is  shown  that  the  memory  deteriorates  as  time  goes  on,  and 
that  the  rate  of  deterioration  is  most  rapid  at  the  outset.  This 
rate  of  forgetting  as  measured  by  Ebbinghaus  is  shown  in* 
Figure  24. 

Meumann  and  others  report  what  they  take  to  be  a  slight 
recovery  of  memory  at  the  end  of  24  hours.13  This  anomaly 
was  not  shown  in  the  careful  work  of  Ebbinghaus  though  a 
tendency  to  such  recovery  may  be  noticed  in  Figure  24.  Meu- 
mann's  subjects  were  unable  to  recall  as  much  9  hours  after 
practice  as  they  could  recall  13  hours  later.  Graphically  re- 
presented, there  was  a  rise  in  the  forgetting  curve  between  the 
9  and  the  24  hour  points.  Many  suppositions  have  been  made 
on  the  basis  of  these  results.  Colvin  says  "This  improvement  in 
memory  seems  to  be  due  to  the  fact  that  the  original  impres- 
sions have  had  an  opportunity  to  become  associated  with  per- 
manent elements  in  consciousness,  and,  therefore,  are  capable 
of  revival  more  readily  after  a  certain  lapse  of  time."14 

From  the  following  experiments  by  Mr.  W.  R.  Wilson 
in  the  local  laboratory  an  interpretation  of  Meumann's  results 
in  terms  of  the  facilitating  action  of  conditioning  stimuli  is 
suggested.  Ten  subjects  learned  lists  of  ten  nonsense  sylla- 
bles, and  72  hours  later  relearned  the  same  lists  sometimes  in 
the  same  surroundings,  and  sometimes  in  different  surround- 
ings. Each  subject  learned  one  list  in  the  laboratory  and  re- 
learned  in  the  laboratory,  learned  a  second  list  in  the  labora- 
tory and  relearned  out  of  doors,  learned  a  third  list  out  of 
doors  and  relearned  in  the  laboratory,  and  learned  a  fourth 
list  out  of  doors  and  relearned  out  of  doors.  In  eight  of  the 
ten  subjects  there  was  greater  saving  in  each  case  where  re- 
learning  occurred  in  the  same  surroundings  in  which  the  first 
learning  had  taken  place.     Two  subjects  showed  in  one  of 

13  Meumann,  Psychology  of  Learning,  Chapter  7,   Sec.   6. 

14  Colrin,    The  Learning  Process,  page  140. 


74 


LEARNING 


100 


do 


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60 


01 
< 

-J 

LLJ 


Q 
> 


20 


2 
UJ 

o 

q: 
u 

OL 


■1.  . 

""H "T-;/-i  '!'!■.[",     i,         n   |!firrr[  '    | 

1  i'; 

1 

'  "  ! ;                       j 

j 

1 

r 

;j 

..! . 

1 

[ 

1 

. 

1 

1 

V 

I 

1  1   1  jj 

!|!|l  i!l  |  i        |i   I   !               IP 

1  '  1     ■     '              1 

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'ii> 

t 

1 

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•.;, ,  ..;     ' j 

j 

j  ' 

■ 

1 

0 

...HOURS 2\Q. k ...,;J4 

A,  „ ^ W* 

Figure  24 — The  rate  of  forgetting  a  nonsense  series.  (After  Ebbinghaus).  The 
amount  of  positive  adaptation  remaining  at  any  time  is  measured  by  the 
saving  method. 


LEARNING  75 

their  four  series  a  greater  saving  where  relearning  had  oc- 
curred under  dissimilar  conditions.  An  average  of  11.4  per 
cent  fewer  repetitions  were  required  to  relearn  in  similar 
surroundings. 

In  another  experiment  the  subject  was  seated  in  a  room 
and  copied  a  list  of  letters  on  a  typewriter  whose  keys  had  been 
arranged  in  a  random  order.  He  copied  the  same  list  24  hours 
later  and  the  times  were  compared.  A  variable  condition  con- 
sisting of  the  presence  or  absence  of  the  odor  of  oil  of  pepper- 
mint was  used.  Each  subject  practised  a  list  with  the  odor 
present  and  repeated  the  same  list  with  the  odor  absent;  he 
then  practised  a  list  with  the  odor  present  and  repeated  the 
list  24  hours  later  with  the  odor  present.  He  then  practised 
with  list  without  the  odor  and  repeated  with  the  odor;  and 
last  practised  without  the  odor  and  repeated  without  the  odor. 
13  subjects  were  used,  and  the  average  saving  in  the  time 
required  to  repeat  the  lists  was  9.4  per  cent  greater  when  the 
repetition  took  place  under  the  condition  of  the  first  practice. 

It  is  highly  probable  that  the  greater  retention  shown  by 
Meumann's  subjects  at  the  end  of  24  hours  depended  upon  the 
daily  recurrence  of  conditioning  stimuli.  There  is  a  diurnal 
rhythm  of  experience  which  results  in  a  characteristic  internal 
state  at  each  hour  of  the  day.  We  sleep,  eat,  work,  and  play 
according  to  a  fairly  rigid  schedule.  The  resulting  periodic 
bodily  states,  present  at  the  original  learning,  contribute  fam- 
iliar stimuli  to  anyone  who  is  engaged  in  relearning  after  a  24 
hour  period.  These  stimuli  come  to  condition  the  responses 
and  facilitate  the  relearning. 

Whole  and  Part  Learning 

One  of  the  practical  questions  which  arises  when  we  have 
something  to  commit  to  memory  is  whether  the  material 
should  be  rehearsed  from  beginning  to  end,  or  broken  up  into 
parts  so  that  each  part  can  be  learned  separately  and  the  parts 
later  combined.  If  the  law  represented  by  Figure  22  held  for 
short  series  as  well  as  for  long,  it  would  take  twice  the  time  to 


76  LEARNING 

learn  any  series  as  to  learn  a  series  half  that  length.  Part 
learning  would  then  evidently  be  wasteful,  because  it  would 
take  the  same  time  to  learn  by  parts  as  to  learn  by  wholes,  and 
after  the  parts  were  learned  the  order  of  the  parts  would  have 
to  be  learned  also.  The  law  (Figure  22)  holds,  however,  only 
for  lengths  somewhat  greater  than  the  memory  span.  This 
memory  span  is  the  amount  which  can  be  accurately  reproduc- 
ed after  a  single  reading.  Because  small  parts  are  memorized 
with  relatively  greater  ease  than  large  parts,  we  have  no  way 
of  determining  in  advance  of  experiment  whether  the  easy 
learning  of  small  parts  compensates  for  the  necessity  of  link- 
ing these  parts  together  after  each  has  been  committed  to 
memory. 

Ebbinghaus  has  shown  that  when  two  series  of  different 
lengths  are  memorized  to  the  point  of  one  perfect  reproduc- 
tion, the  longer  series  is  better  retained  after  24  hours  than  is 
the  shorter  series.  Thus,  33  percent  of  a  12  syllable  series  is 
shown  by  the  saving  method  to  persist  after  the  lapse  of  one 
day,  whereas  48  percent  of  a  24  syllable  series  is  retained.  This 
fact,  taken  in  conjunction  with  the  law  (Figure  22)  that  an 
increase  in  the  length  of  the  series  demands  a  corresponding 
increase  in  the  amount  of  work  required  for  learning,  gives  us 
reason  to  expect  that  experimental  results  will  show  a  saving 
when  the  method  of  learning  by  wholes  is  employed. 

Experimental  results  demonstrate  conclusively  that  part 
learning  is  wasteful  and  whole  learning  most  efficient.  The 
whole  method  requires  less  work  for  a  single  accurate  repro- 
duction, and  for  a  given  amount  of  work  done  results  in  fewer 
errors  and  better  retention.  This  holds  true  for  both  nonsense 
material  and  for  meaningful  material.1"' 

Results  of  the  Distribution  of  Practice 

If  we  have  a  certain  amount  of  time  to  spend  in  mem- 
orizing, it  is  found  advantageous  to  distribute  this  time  over 

15   Lyoi       Wetno  >•   and    the    Learning   Proce**;    Pechstein,    Whole    vs.    rnrt    Methods    in    Motor 
Learning,  i    Monographs,    1917;    Pyle,    Economical    Learning,    Journal    of    Educational 

Psychology,  i<u:;.  pages  148-168;  Pyle  and  Snyder,  The  Matt  Economical  Unit  for  Committing  to 
Memory,  Journal  of  Educational  Psychology,   1911,   pages  133-142. 


LEARNING  77 

several  days  rather  than  to  utilize  it  all  at  one  sitting.  Eb- 
binghaus  found  that  a  12  syllable  series  repeated  68  times 
consecutively  required  7  repetitions  for  relearning  24  hours 
later.  Series  of  the  same  length  repeated  on  an  average  of  17.5 
times  the  first  day,  12  times  the  second  day,  and  8.5'  times  the 
third  day  (38  in  all)  needed  but  5  repetitions  for  relearning  on 
the  fourth  day.  It  is  evident  from  this,  and  from  similar  re- 
sults which  have  been  found  for  meaningful  material,  that 
economy  of  learning  demands  distributed  repetitions. 

Lashley  has  shown  that,  in  training  white  rats  to  choose 
the  path  leading  to  food,  using  two  trials  a  day  saved  69  per- 
cent of  the  work  which  would  have  been  necessary  if  ten  trials 
a  day  had  been  used.16 

Learning  a  prose  passage  verbatim,  committing  verse  to 
memory,  or  learning  to  say  a  set  of  nonsense  syllables  as  in 
Ebbinghaus'  experiments,  is  the  acquisition  of  serial  response 
habits.  When  the  practice  begins,  each  printed  symbol  is  the 
stimulus  for  a  response  which  has  been  already  attached  to 
this  symbol  by  conditioning.  As  the  stimuli  occur  in  a  given 
order,  the  reactions  follow  each  other  in  a  given  order,  and 
with  a  sufficient  number  of  repetitions  the  serial  response  is 
established  independent  of  visual  stimuli  but  dependent  upon 
proprioceptive  and  auditory  stimuli. 

In  learning  nonsense  syllables  the  learner  is  wholly  unac- 
customed to  the  order  of  the  responses,  and  the  series  must  be 
learned  from  the  beginning.  In  dealing  with  words,  on  the 
other  hand,  the  learner  is  seldom  without  some  previous  ex- 
perience of  their  sequence,  and  when  committing  to  memory 
ordinary  prose  he  relies  very  largely  upon  already  formed  se- 
rial response  habits.  Familiarity  makes  relatively  easy  his  re- 
membering combinations  of  "sensible"  words.  The  meaning- 
fulness  of  language  is  a  further  aid  to  prose  learning.  This 
reenforcement  is  partly  composed  of  gesture  and  characteris- 
tic emotional  expression,  of  customary  pitch,  speed,  and  in- 
tensity variations  of  the  voice.    The  response  tendencies  which 

16  Lashley,   A   Simple  Maze.;  with   data   on  the  relation  of  the  distribution  of  practice   to   the 
rate  of  learning,   Psyehobiology,   1918,  pages  353-3G7. 


78  LEARNING 

are  touched  off  by  each  of  the  spoken  words  also  play  their 
part  in  the  reenforcement. 

Some  prose  is  easy  to  commit  to  memory,  whereas  other 
prose  is  difficult.  Easy  prose  contains  sterotypisms  and  fam- 
iliar word  combinations.  Less  stupid  and  more  original  texts 
combine  words  in  a  less  predictable  order,  and  so  are  more  dif- 
ficult to  memorize  or  even  to  read.  Verse  is  easy  to  learn  on 
account  of  its  set  rhythm  and  its  predictable  end  rhymes. 

Trial  and  Error 

Certain  organisms  such  as  paramoecium  have  for  the 
most  part  but  a  single  manner  of  response.  This  is  given  to  ev- 
ery harmful  situation  which  the  animal  meets  in  its  forward 
swimming  and  consist  in  backing,  turning  to  one  side,  and  then 
proceeding  in  a  new  direction.  If  this  response  brings  it  again 
into  harmful  conditions,  the  response  is  repeated  until  the  ani- 
mal is  progressing  through  a  medium  which  contains  no  stim- 
uli for  this  negative  reaction.  When  an  animal  makes  many 
trials,  any  one  of  which  may  or  may  not  be  specially  fitted  to 
remove  the  animal  from  harm  or  bring  it  into  better  surround- 
ings, and  when  as  a  result  of  these  trials  it  finally  stumbles 
upon  the  suitable  response,  its  behavior  is  called  trial  and 
error.11 

Trial  and  error  enters  into  the  behavior  of  all  animals. 
When  hungry  they  are  likely  to  range  about  until,  after  many 
fruitless  reactions,  they  at  last  come  by  chance  upon  food  or 
the  signs  of  food.  In  the  same  way  mates  are  discovered,  new 
shelter  is  found,  or  building  materials  secured.  The  trial  and 
error  behavior  of  most  higher  animals  differs  from  that  of 
the  lowest  forms  in  exhibiting  not  one  but  many  different 
kinds  of  response.  If  we  place  a  cat  in  a  "puzzle  box,"  the 
door  of  which  only  opens  when  the  cat  pulls  a  string  or  turns  a 
knob,  the  cat  will  make  many  kinds  of  unsuccessful  movement 
before  it  accidentally  hits  upon  the  proper  means  of  escape. 

17  Thomdike,   Animal  Intelligence,  page  35ff. 


LEARNING  79 

Most  inventions  and  discoveries  are  the  result  of  happy 
accidents.  Charles  Lamb's  hypothesis  of  the  origin  of  roast 
pig  is  not  wholly  fanciful.  We  may  be  certain  that  the  dis- 
covery of  intoxicating  beverages  was  due  to  the  carelessness 
of  some  primitive  housewife  who  left  her  fruit  to  spoil  but 
whose  frugality  prompted  a  reluctant  use  of  a  concoction 
whose  hidden  possibilities  must  soon  have  had  a  wide  publicity. 

A  series  of  trial  and  error  responses  may  in  certain  cases 
become  a  habit  through  the  agency  of  conditioning  stimuli  in 
the  manner  described  in  the  discussion  of  serial  responses.  It 
is  very  seldom,  however,  that  the  series  of  trial  and  error  re- 
sponses as  a  whole  becomes  fixed  as  a  habit.  Usually  the  se- 
ries is  shortened  in  the  process  of  habit  formation,  the  final 
response  being  given  but  many  of  the  futile  responses  that  pre- 
ceded it  being  eliminated.  We  may  now  ask  the  question  how 
this  shortening  of  the  series  is  accomplished. 

The   Shortening  or  a  Trial  and  Error   Series  into  a  Finae 

Habit  Response 

When  considering  the  subject  of  threshold  of  response 
we  found  that  a  stimulus  may  be  too  weak  to  elicit  any  move- 
ment. When  a  stimulus  is  above  the  threshold,  the  kind  of  re- 
action which  it  causes  may  depend  upon  its  intensity.  It  is 
a  general  principle  that  most  stimuli,  which  when  weak  cause 
an  approach  reaction,  cause  avoidance  when  they  become  very 
intense.  This  is  illustrated  by  taste  stimuli.  The  sourness  of 
lemonade  and  the  bitterness  of  coffee  can  be  increased  to  a 
point  where  these  drinks  are  avoided.  A  limited  amount  of 
salt  is  necessary  to  make  eggs  palatable,  but  when  exceeded 
causes  avoidance.  Children  instinctively  seek  sweet  food,  but 
food  may  be  so  sweet  as  to  become  disgusting.  The  resistance 
that  a  little  child  shows  to  rough  handling  may  be  replaced  by 
acquiescence  to  gentle  manipulation.  The  baby  accepts  more 
readily  the  nipple  of  his  nursing  bottle  when  it  is  gently  placed 
in  his  mouth  than  when  it  is  forcibly  inserted. 


80  LEARNING 

The  response  which  a  new  born  baby  gives  to  a  stimulus  is 
definitely  determined  by  the  innate  structure  of  his  nervous 
system,  although  there  may  be  minor  fluctuations  of  response 
in  the  same  infant  at  different  times  due  to  such  physiological 
changes  as  hunger  or  fatigue.  His  response  tendencies  are 
in  large  part  predictable.  He  naturally  responds  by  grasping, 
looking,  withdrawing,  or  other  movements  according  to  the 
nature  of  the  stimulus.  Thus  approach  and  avoidance  are  not 
chance  behavior,  and  the  fact  that  all  people  learn  in  much 
the  same  way  is  due  to  their  being  equipped  to  respond  to  a 
given  stimulus  by  the  same  reaction.  Many  of  these  reactions 
are  simple  reflexes. 

The  more  remote  an  object  is,  the  less  intense  is  its  stim- 
ulation. Approach  to  the  object  gradually  increases  the  in- 
tensity of  this  stimulation  and  in  certain  cases  an  intensity  may 
be  reached  which  causes  a  turning  away.  Thus  the  increasing 
stimulation  of  a  single  sense  organ  often  results  successively 
in  opposite  orientations. 

In  many  cases  the  result  of  approaching  an  object  is  to 
bring  stimuli  to  bear  upon  sense  organs  not  at  first  affected. 
A  single  object  may  be  the  source  of  stimuli  first  to  distance 
receptors,  such  as  eyes,  ears,  or  nose,  and  later  to  the  sense 
organs  in  the  skin,  muscles,  and  tendons.  When  a  deer  ap- 
proaches at  the  sight  of  a  man,  not  only  does  the  visual  stim- 
ulus increase  in  intensity,  thus  tending  to  make  the  deer  take 
flight,  but  its  greater  proximity  to  the  man  brings  into  play 
odor  stimuli,  in  response  to  which  the  deer  turns  away.  This 
succession  of  approach  and  avoidance  is  characteristic  of  most 
trial  and  error  behavior.18 

The  incompatibility  between  approach  and  avoidance  is 
for  the  most  part  an  incompatibility  of  orientations.  The 
movements  of  locomotion  made  by  the  deer  are  not  funda* 
mentally  different  in  approach  and  in  retreat.  The  difference 
lies  in  the  direction  in  which  the  deer  is  turned.   This  makes 

13  Holmes,   StudU«   in  Animal   Behavior,   Chapter  VII;   Watson,   Psychology,   Chapter  8. 


LEARNING  81 

evident  the  importance  of  the  analysis  of  movement  groups  in- 
to their  component  parts. 

There  is  a  classical  example  of  the  baby  and  the  candle 
The  baby  seeing  the  flame  approaches  his  finger,  and  on  feeling 
the  flame  withdraws  his  finger.  If  charged  wires  are  placed  be- 
fore the  opening  of  a  rat's  food  box,  so  that  the  animal  in 
stepping  upon  them  receives  a  mild  punishment,  his  approach 
is  followed  by  avoidance.  If  a  bird  takes  a  bite  of  a  cinnabar 
caterpillar  the  taste  makes  it  reject  the  food.  The  master  who 
does  not  enjoy  the  friendly  greeting  of  the  dog  that  places 
his  dirty  forepaws  on  clean  clothing,  causes  the  dog  to  de- 
sist by  stepping  on  the  hind  feet  of  the  animal.  In  all  these 
cases  while  the  approach  stimulus  is  still  present  the  avoidance 
reaction  has  been  called  forth.  The  result  is  that  the  avoidance 
reaction  is  now  conditioned  by  the  approach  stimulus,  so  that 
the  avoidance  response  tends  to  be  given  as  soon  as  the  ap- 
proach stimulus  is  received.  The  sight  of  the  flame  has 
become  the  conditioning  stimulus  for  withdrawing  the  finger. 
The  sight  of  the  door  of  the  food  box  has  become  the  condition- 
ing stimulus  for  turning  away.  The  sight  of  the  caterpillar 
has  become  the  conditioning  stimulus  for  rejecting  the  food. 
The  sight  of  the  master  has  become  the  conditioning  stimulus 
for  returning  to  all  fours.  In  addition  to  the  conditioning  vis- 
ual stimuli  involved  in  these  responses,  the  proprioceptive 
stimuli  brought  about  by  the  approach  movements  serve  to 
condition  the  movements  of  withdrawal. 

It  is  obviously  impossible  for  the  baby  to  extend  and 
withdraw  its  hand  at  the  same  time,  for  the  rat  simultaneous- 
ly to  approach  and  retreat  from  the  door,  for  the  bird  to  eat 
its  caterpillar  while  rejecting  it,  or  for  the  dog  to  paw  his  mas- 
ter while  backing  away.  The  interference  of  these  opposed 
'movements  may  not,  on  the  second  occurrence  of  the  approach 
stimulus,  prevent  the  succession  of  approach  and  avoidance, 
but  eventually  repetition  establishes  the  conditioned  response 
more  firmly,  so  that  in  the  end,  provided  the  avoidance  stim- 


82  LEARNING 

ulus  is  sufficiently  strong,  the  approach  response  ceases  to  be 
given.  This  is  due  to  the  gradual  lowering  of  threshold  of  the 
avoidance  response  as  elicited  by  the  approach  stimulus  and 
the  resulting  mutual  inhibition  of  the  two  opposed  response 
tendencies.  When  this  occurs  we  say  the  baby  is  trained  to 
avoid  the  candle,  the  rat  to  avoid  the  door,  the  bird  to  let  the 
caterpillar  alone,  and  the  dog  to  proper  conduct. 

Emotional  reenforcement  is  usually  associated  instinct- 
ively with  avoidance  responses.  Running  away  is  accom- 
panied by  fear ;  rejecting  food,  by  nausea ;  averting  the  eyes, 
by  disgust  or  shame ;  withdrawing  the  burnt  hand,  by  grief ; 
turning  away  from  insuperable  obstacles,  by  annoyance.  The 
responses  to  all  pain  stimuli  are  emotionally  facilitated.  This 
emotional  reenforcement  makes  avoidance  relatively  more 
energetic  than  approach,  and  so  in  the  rivalry  of  two  incom- 
patible responses  it  is  likely  to  prevail. 

The  approach  responses  in  mating  and  food-getting  have 
strong  emotional  reenforcements.  Thus,-  because  of  appetite, 
these  approach  movements  are  often  carried  out  to  the  disre- 
gard of  stimuli  which  would  otherwise  cause  withdrawal.  Neg- 
ative adaptation  to  the  disregarded  avoidance  stimuli  then  oc- 
curs. Within  certain  limits,  the  longer  the  period  of  fasting  or 
continence,  the  greater  is  the  emotional  reenforcement  and  the 
more  aggressive  the  approach  movements.  This,  along  with 
the  fact  that  abortive  behavior  of  this  sort  calls  out  further 
emotional  reenforcement,  assures  the  final  success  of  food- 
getting  and  mating. 

Let  us  consider  again  the  case  of  a  cat  placed  in  the  puz- 
zle box.  After  many  fruitless  movements  he  is  attracted  by 
the  button,  the  turning  of  which  opens  the  door.  After  the  cat 
has  been  placed  repeatedly  in  the  box,  the  time  required  for 
escape  becomes  gradually  less,  and  the  fruitless  movements 
grow  fewer,  until  finally  the  cat's  being  placed  in  the  box  may 
be  followed  at  once  by  the  successful  response  of  turning  the 
button. 


LEARNING  83 

The  cat  when  in  confinement  is  instinctively  organized  to 
respond  to  the  sight  of  bars,  cracks,  corners,  and  even  solid 
walls  by  approaching  and  pulling  and  pushing  with  paws, 
claws,  nose  and  teeth.  If  any  part  of  the  box  is  loose,  the  cat 
has  a  tendency  to  continue  his  manipulation.  He  is  also  in- 
stinctively organized  to  turn  away  from  these  same  objects 
when  they  offer  more  than  a  certain  amount  of  resistance  to 
his  attack. 

The  situations  which  the  cat  faces  in  the  puzzle  box  are 
for  the  most  part  composed  of  visual  stimuli  which  attract 
him,  followed  by  stimuli  to  his  proprioceptors  and  sense  organs 
of  touch  which  repel  him,  and  these  two  classes  of  stimuli  are 
given  by  the  same  object.  He  is  instinctively  attracted  by  the 
sight  of  the  bars,  but  on  reaching  them,  especially  if  they  are 
rigid,  he  is  instinctively  impelled  to  turn  away.  This  turning 
away  is  due  to  the  resistance  of  the  bars  to  his  attempted  man- 
ipulation and  to  his  efforts  to  force  his  way  between  them.  Ap- 
proach and  retreat  are  here  original  tendencies  called  forth  by 
a  single  object. 

With  repetition  the  sight  of  the  bars  becomes  the  condi- 
tioning stimulus  for  retreat,  so  that  the  conditioned  response 
inhibits  the  original  response.  One  by  one  the  movements  of 
approach  to  the  various  confining  surfaces  of  the  box  are  in- 
hibited by  the  conditioned  responses  of  retreating,  until  at 
last  the  animal  is  attracted  by  the  door-opening  device.  The 
reason  that  this  last  movement  is  not  inhibited  is  that  the  device 
itself  never  serves  as  the  source  of  a  stimulus  which  is  instinct- 
ively avoided.  Although  the  cat  turns  away  from  the  button 
in  response  to  the  open  door,  he  does  so  not  because  the  but- 
ton repels  him  but  because  the  open  door  attracts  him.  Ap- 
proaching the  button  and  approaching  the  open  door  are  the 
only  approach  responses  which  are  uninhibited  by  conditioned 
avoidance  responses,  and  while  the  door  is  closed  the  button 
alone  calls  forth  an  uninhibited  response. 

When  the  cat  is  but  partially  trained  he  makes  useless 


84  LEARNING 

responses  to  various  parts  of  the  box.  He  always  ends,  how- 
ever, by  making  the  successful  response  and  by  escaping.  As 
some  useless  responses  are  given  on  some  occasions  and  others 
on  other  occasions,  depending  upon  the  cat's  chance  position 
in  the  box,  the  successful  response,  always  occuring,  is  likely 
to  be  the  one  most  practised.  This  may  be  another  factor  in 
lowering  the  threshold  of  response  to  the  door-opening  de- 
vice.19 

Mutual  inhibition  of  two  incompatible  response  tenden- 
cies may  result  from  other  kinds  of  situations  than  one  in 
which  the  same  object  furnishes  both  approach  and  avoidance 
stimuli.  If  a  dog  is  tickled  on  both  sides  simultaneously,  the 
usual  scratch  reflex  may  be  elicited  from  neither  side.20 
Here  two  approach  responses  serve  to  inhibit  each  other  be- 
cause the  tickling  of  each  side  produces  a  contralateral  exten- 
sion of  the  hind  leg  as  well  as  the  oscillatory  scratching  move- 
ments of  the  leg  on  the  side  stimulated.  As  both  legs  are  ac- 
tuated both  to  scratch  and  to  support  by  the  bilateral  stimula- 
tion, and  as  these  movements  are  incompatible,  there  may  re- 
sult either  no  movement  at  all  or,  because  of  the  unstable 
equilibrium  of  this  system,  an  alternation  of  scratching  on  the 
two  sides.  It  is  only  this  unstable  equilibrium  which  makes  in- 
credible the  case  of  Buridan's  ass,  who,  the  victim  of  balanced 
approach  tendencies,  starved  while  standing  between  two 
stacks  of  hay.20 

A.  more  stable  equilibrium  is  found  where  an  animal  is 
hemmed  in  by  avoidance  stimuli.  The  cat  hesitates  to  take  to 
the  water  when  pursued  by  a  dog.  The  victim  in  a  burning 
building  is  repelled  by  both  the  fire  and  the  long  drop  to  the 
street.  In  daily  life  we  are  often  placed  between  the  devil  and 
the  deep  sea. 

When  trial  and  error  behavior  does  not  involve  avoidance 
responses,  many  fruitless  movements  may  be  retained  in  the 

1!)   Smith,    The    l.imi'*   of  ^durability   in  Paramoccium.   Journal   of   Comparative   Neurology  and 
Psychology,   1902,   page   503. 

20  Sherrington,   The  Integrative  Action  of  the  Nervous  System,  page  143. 


LEARNING  85 

resulting  habit.  The  self-educated  bricklayer  is  likely  to  pre- 
serve many  superfluous  motions  which  are  the  results  of  the 
chance  arrangement  of  his  materials  at  the  time  he  first  be- 
gan to  learn  the  trade.  If  an  inconveniently  placed  brick,  or 
an  awkward  manner  of  handling  his  trowel,  had  always  been 
the  stimulus  for  an  avoidance  response,  as  of  course  it  occa- 
sionally is,  he  would  not  have  developed  his  unskillful  and  cost- 
ly habit.  The  instruction  which  a  bricklayer  receives  consists 
in  verbal  directions  and  criticisms  which  compensate  for  the 
absence  of  innate  avoidance  stimuli.  The  same  is  true  of  learn- 
ing a  golf  stroke,  learning  to  play  a  violin,  or  learning  to  sing. 
In  social  behavior  the  moral  code  serves  in  the  absence  of 
avoidance  stimuli  to  inhibit  acts  which  endanger  common  wel- 
fare, leaving  free  from  interference  only  acts  of  virtue. 

The  reason  that  such  habitual  serial  responses  as  signing 
one's  name,  whistling  a  melody,  or  reciting  a  poem,  undergo 
no  shortening  is  that  these  acts  do  not  bring  avoidance  stimuli 
into  play. 

It  has  been  pointed  out  before  that  many  acts  are  made 
up  of  movements  of  orientation,  locomotion,  and  interven- 
tion. It  is  not  necessary  that  orientation  should  be  complete 
before  locomotion  begins,  or  that  locomotion  should  be  finished 
before  movements  preparatory  to  intervention  are  commenc- 
ed. In  a  practised  act,  such  as  picking  up  a  book  from  the  floor, 
we  do  not  first  turn  toward  the  book,  walk  to  the  spot,  bend  the 
body,  extend  the  arm,  and  grasp  the  book,  all  separately.  We 
are  more  likely  to  start  walking  as  we  turn,  bend  the  body  and 
extend  the  arm  as  we  walk,  and,  while  grasping  the  book,  turn 
the  body  preparatory  to  walking  away. 

When  a  number  of  acts  form  a  serial  response,  one  act 
is  seldom  completed  before  the  next  is  begun.  In  this  way  there 
is  an  overlapping  of  compatible  movements,  orientation  for 
the  next  act  occurring  while  the  movements  of  intervention  of 
the  last  act  are  still  in  progress.  This  telescoping:  of  one  act 


86  LEARNING 

with  another  is  one  of  the  factors  in  shortening  the  time  of 
a  serial  response. 

Where  overlapping  of  acts  occurs,  more  movements  are 
made  at  the  same  time  and  so  more  movement-produced  con- 
ditioning stimuli  are  available  to  knit  together  the  parts  of  the 
series. 

As  a  series  of  acts  is  repeated  time  and  again,  the  degree 
of  overlapping  of  the  individual  acts  increases  more  and  more 
until  limited  by  the  anatomical  structure  of  the  animal  or  by 
the  requirements  of  the  situation.  This  overlapping  is  made 
possible  by  the  fact  that  many  conditioning  stimuli  have  been 
acting  for  some  time  before  the  response  which  they  have 
come  to  condition  has  occurred.  As  we  approach  a  door  and 
finally  see  the  keyhole  we  reach  for  our  keys.  Later,  because 
we  saw  the  door  while  reaching  for  the  keys,  we  take  out  our 
keys  when  we  first  come  in  sight  of  the  door.  The  key-reach- 
ing response,  having  been  established  to  the  sight  of  the  door, 
may  be  given  while  opening  the  gate,  provided  the  door  is  in 
view.  Thus  the  response  may  next  be  conditioned  by  the  gate 
opening,  and  later  still  by  the  sight  of  the  gate  in  the  distance. 

In  the  same  way,  due  to  the  overlapping  of  the  parts  of 
situations,  a  dog  first  responds  to  the  sight  of  members  of  the 
family,  then  to  their  footsteps,  then  to  the  sound  of  the  train 
on  which  they  regularly  arrive. 

Ease,  grace  of  movement,  or  the  facile  performance  of  a 
difficult  act  does  not  come  with  maturity  alone,  but  requires 
practice.  Coordinated  movements  are  guided  by  stimuli  in 
the  external  situation,  or  by  stimuli  which  are  movement-pro- 
duced. Each  movement  is  attached  to  its  stimulus  by  original 
nature  or  by  conditioning,  and  the  proper  energy  of  each 
movement  is  learned  by  experience.  In  picking  up  a  brick  we 
grip  it  sufficiently  to  keep  it  from  slipping  out  of  the  hand, 
take  up  a  posture  which  prevents  our  being  overbalanced  by 
the  weight,  and  lift  with  sufficient  force  to  raise  the  brick  from 
the  ground.  In  the  process  of  learning,  the  brick  and  each  an- 


LEARNING  87 

tecedent  movement  furnish  the  conditioning  stimuli  for 
each  part  of  the  act.  We  employ  a  very  different  prehension, 
posture,  and  lift  in  picking-  up  a  sponge.  We  are  not  conscious 
of  this  difference  in  behavior  unless  the  object  which  we  pick 
up  has  a  deceptive  appearance. 

Awkwardness  is  eliminated  by  trial  and  error,  and  by  the 
dropping  out  of  incompatible  movements  which  constitute  mis- 
takes. We  adjust  the  force  of  muscular  contractions  to  the 
work  which  is  to  be  done.  Such  adjustments,  together  with  the 
elimination  of  false  moves  and  the  telescoping  of  successive 
acts,  results  in  a  maximum  simplicity  of  the  effective  response, 
and  this  we  call  coordination  or  eusynergia. 

The  nervous  structure  which  governs  many  coordinated 
acts  is  a  matter  of  original  nature  alone.  Birds  and  insects  fly 
without  practice ;  the  baby  balances  on  his  two  feet  by  means 
of  a  neural  mechanism  which,  though  it  improves  with  use,  is 
an  endowment  of  great  effectiveness ;  nursing  movements  oc- 
cur in  an  orderly  combination  and  sequence.  The  extent  to 
which  the  cerebral  cortex  is  involved  in  learned  coordination 
zvhere  the  sequence  of  movements  is  independent  of  stimuli  re- 
mains somewhat  a  matter  of  conjecture.  It  is  not  probable, 
however,  that  an  elaborate  series  of  movements  may  be  coor- 
dinated by  cortical  processes  independent  of  movement-pro- 
duced stimuli. 

Imitation 

When  a  response  resembles  its  stimulus,  we  call  the  re- 
sponse imitation.  We  laugh  on  hearing  others  laugh.  A  fright 
response  spreads  from  individual  to  individual  in  the  herd. 
One  sheep  jumps  the  fence  because  the  preceding  sheep  jump- 
ed it.  The  barking  of  one  dog  causes  all  the  dogs  of  the  neigh- 
borhood to  join  in.  On  seeing  a  person  studying  the  sky  we 
stop  and  do  likewise.  When  a  cage  of  pigeons  is  supplied  with 
water  the  water  may  not  be  noticed  for  some  time,  but  when 
one  pigeon  begins  to  drink  several  others  will  usually  perform 
the  same  act.  Smoking,  yawning,  whistling,  throwing  stones  at 


88  LEARNING 

a  target,  rising-  and  going  home,  hissing  and  applauding,  are 
stimuli  which  readily  call  out  imitation  in  others. 

Tickling  is  probably  the  original  stimulus  which  causes 
a  baby  to  smile.  He  does  not  at  first  smile  by  imitation,  but 
in  order  to  learn  to  imitate  he  must  have  someone  present  to 
smile  back  at  him.  If  the  sight  of  a  smiiing  face  accompanies 
the  baby's  act  of  smiling  it  thereby  conditions  his  response  and 
will  later  cause  him  to  smile  in  the  absence  of  tickling. 

Practically  all  imitative  behavior  is  made  up  of  condition- 
ed responses,  there  being  very  few  cases  of  instinctive  imita- 
tion. These  few  cases  are  probably  limited  to  the  tendency  of 
lower  animals  to  run,  swim,  and  fly  together,  to  orient  them- 
selves in  the  same  direction,  and  to  follow  one  another.  The 
instinct  of  following  is  very  often  the  act  of  approaching  some- 
thing which  is  moving  away.  This  analysis  applies  rather  to 
the  following  of  fawns,  kittens,  and  puppies  than  to  the  fol- 
lowing of  chicks.  In  the  case  of  the  fawn  which  follows  its 
mother  in  her  flight  the  approach  response  is  very  evident,  for 
when  the  mother  stops  the  fawn  nestles  against  her. 

The  dependence  of  imitation  on  learning1  is  well  illustrat- 
ed by  language  acquisition.  The  baby  is  at  first  moved  to  make 
a  great  variety  of  vowel  and  consonant  sounds  by  such  stimuli 
as  he  receives  from  a  moderately  full  stomach,  a  soft  bed,  and 
a  warm,  well-lighted  room.  The  sounds  he  makes  accompany 
the  movements  which  produce  them  and,  because  the  vowrels 
are  sustained  and  the  consonants  either  sustained  or  repeated, 
these  sounds  also  precede  the  movements  which  continue  or 
reiterate  them.  They  thus  become  the  conditioning  stimuli  for 
their  own  production,  so  that  when  uttered  by  others  they  are 
imitated  by  the  baby.  A  period  of  practice,  during  which  the 
baby  plays  with  these  sounds,  is  necessary  before  imitation 
is  possible,  and  by  this  practice  the  baby  is  prepared  to  im- 
itate the  particular  sounds  of  any  language. 

Imitation  is  seldom  an  exact  replica  of  the  act  which  is 
imitated.   The  imitator's  response  is  that  habitual  act  of  his 


LEARNING  89 

which  most  nearly  resembles  the  act  which  he  observes.  As 
a  person  grows  older,  his  reaction  tendencies  become  less  vari- 
able and  more  stereotyped.  Thus  a  child  is  in  many  ways  a 
better  mimic  than  is  an  adult.  If,  for  example,  in  his  playing 
with  sounds  a  baby  has  familiarized  himself  with  a  certain 
French  vowel,  he  is  likely  to  imitate  it  with  considerable  ac- 
curacy, whereas  an  adult,  whose  language  responses  have 
throughout  a  lifetime  of  practice  been  confined  to  English 
sounds,  will  imitate  the  French  vowel  by  its  nearest  approx- 
iation  in  his  native  tongue. 

In  New  England  the  invocation,  "O  mihi  beate  Martine," 
is  found  in  degenerate  form  as  the  exclamation,  "Oh  my  eyes 
and  Betty  Martin."  The  baseball  player  in  his  first  attempts 
at  golf  imitates  a  golf  stroke  inaccurately  because  of  his  fam- 
iliarity with  a  bat.  One  of  the  reasons  that  it  is  hard  to  learn 
to  dive  is  because  we  have  learned  so  well  to  jump  feet  fore- 
most. The  motion  picture  actor's  failure  to  imitate  the  behavior 
of  a  social  class  to  which  he  does  not  belong  is  the  product  of  a 
life  spent  in  acquiring  a  manner  of  quite  another  sort.  The 
plasticity  of  children  lies  in  their  relative  freedom  from  ster- 
eotyped habits.  The  behavior  of  an  adult  falls  into  ruts  from 
which  he  extricates  himself  only  with  great  difficulty. 


CHAPTER  4 
THE  BEHAVIOR  OF  BABIES 

A  baby  that  is  just  born  is  almost  wholly  lacking  in  ex- 
perience. Although  for  some  time  before  birth  the  sense  or- 
gans, the  nervous  system,  and  the  muscles  are  sufficiently  ma- 
ture to  function,  as  proved  by  the  behavior  of  premature  in- 
fants, the  child's  isolation  and  confinement  prevent  any  very 
elaborate  responses. 

At  birth  the  infant  enters  a  world  rich  in  situations,  and 
a  world  permitting  freedom  of  movement.  He  then  for  the  first 
time  experiences  light,  odor,  temperature,  and  cutaneous  pain 
stimuli.  He  then  draws  his  first  breath,  cries,  swallows, 
coughs,  sneezes,  nurses,  and  fixates  objects  with  his  eyes.  He 
is  still  a  creature  of  reflexes,  although  some  of  these  reflexes 
such  as  the  movements  of  nursing,  occur  in  fairly  predictable 
series.  The  stimuli  which  determine  such  a  series  are  in  part 
movement-produced  and  in  part  provided  by  the  external 
world. 

If  each  reaction  of  a  baby  were  the  only  stimulus  causing 
its  next  reaction,  it  would  soon  lose  its  way  in  the  world  and 
perish.  Fortunately,  however,  it  is  guided  by  a  world  of  order- 
ly situations.  Conversely,  if  the  baby  had  no  original  organ- 
ization to  determine  in  part  the  sequence  of  reactions,  the  baby 
would,  by  trial  and  error  learning,  have  to  establish  the  order 
of  the  minute  parts  of  all  the  serial  responses  necessary  for  its 
survival  from  birth.  Otherwise  it  could  live  only  in  situations 
which  would  call  out  in  the  proper  order  the  parts  of  each  re- 
sponse. That  one  act  mav  lead  to  another  without  learning, 
and  with  but  little  guidance  from  external  stimuli,  is  well  il- 
lustrated in  some  of  the  coordinated  movements  of  new  born 
animals. 

It  is  extremely  probable  that  in  all  practised  behavior  each 
step  of  a  serial  reaction  is  caused  in  part  bv  the  movement- 
produced    stimuli  of  the  step  which  precedes  it. 

(90) 


THE  BEHAVIOR  OF  BABIES  91 

The  baby's  endowment  consists  of  relatively  simple  mech- 
anisms, in  contrast  to  the  ready  made  equipment  of  most  of 
the  lower  animals.  Compared  with  the  wasp  which  flies,  stings, 
and  secures  its  own  food  from  the  time  it  leaves  its  cell,  the 
baby  has  much  to  learn.  Tt  is  here  that  the  child's  capacity  for 
acquiring  conditioned  responses  compensates  for  its  early  help- 
lessness, and  secures  for  it  in  the  end  an  integration  of  be- 
havior much  more  elaborate  than  that  of  an  insect.  The  num- 
ber as  well  as  the  simplicity  of  the  responses  which  are  ready  to 
be  attached  to  the  child's  private  environment  contributes  to 
this  ultimate  superioritv. 

Whereas  the  lower  animals,  in  response  to  any  one  of  a 
number  of  stimuli,  make  the  same  elaborately  coordinated 
movement  involving  many  effectors,  the  baby  responds  to  each 
stimulus  with  a  simpler  bodily  movement,  but  with  a  move- 
ment more  particularly  reserved  for  that  element  of  the  situa- 
tion. In  this  way  the  behavior  of  the  human  infant  exhibits 
frequent  incongruities  and  combinations  of  reaction  which 
interfere  with  one  another.  Gradually  his  responses  are  coor- 
dinated and  adjusted  to  his  world  in  a  fashion  which  has 
already  been  described  under  the  heading  "Shortening  of  a 
Trial  and  Error  Series". 

Thus  the  instincts  of  babies  are  more  numerous  and  less 
complex  than  are  the  instincts  of  the  young  of  other  species. 
Human  beings  are  not  endowed  with  ready  formed  tendencies 
to  fight,  hunt,  swim,  or  build  shelter.  All  such  acts  in  man 
are  learned.  Even  putting  out  the  hand  and  grasping  an 
object  may  be  an  art  acquired  by  trial  and  error.  Suckling 
and  the  emotional  responses  are  the  most  elaborate  of  man's 
instinctive  coordinations.  The  movements  involved  in  these 
acts  are  stereoptyped  in  order  and  in  kind,  and  these  action 
patterns  maintain  in  large  part  their  integrity  throughout  life. 

Although  suckling  is  primarily  a  function  of  the  enteric 
tract,  the  whole  body  is  involved  in  the  instinct.  If  the 
baby  is  gently  tickled  on  the  side  of  the  mouth  or  on  the  cheek 


92  THE  BEHAVIOR  OF  BABIES 

the  head  is  moved  so  as  to  engage  the  stimulating  object  with 
the  mouth.  In  finding  the  breast  the  baby  is  thus  guided  by 
the  erectile  mammilla ;  the  lips  and  tongue  form  close  contact 
with  the  breast,  and  suction  is  produced  by  movements  of  the 
tongue  and  jaws.  When  milk  is  taken  into  the  mouth  it  is 
the  stimulus  to  swallowing.  The  hands,  arms,  and  legs  serve 
for  prehension  and  support,  and  thus  assist  the  child  in  nurs- 
ing. 

It  will  be  seen  that  each  step  in  the  series  of  nursing  move- 
ments is  an  act  of  intervention  which  brings  about  the  stim- 
ulus for  the  next  movement.  Each  step  may,  however,  oe  elici- 
ted independently  by  the  proper  stimulus.  On  the  other  hand, 
hunger  probably  reduces  the  threshold  of  all  nursing  move- 
ments, so  that  in  this  sense  at  least  component  parts  of  the 
act  are  bound  together  by  an  implicit  connection  in  the  child's 
nervous  system. 

Many  careful  observations  and  experiments  have  been 
made  upon  babies  from  birth  in  order  to  discover  the  nature  of 
their  instinctive  responses.1  The  maternity  hospital  affords 
excellent  opportunity  for  this  work  during  the  first  few  weeks 
of  the  baby's  life.  Movements  made  by  an  infant  at  birth  may 
be  regarded  as  natural  tendencies  unaffected  by  habit  forma- 
tion. Responses  made  after  a  baby  is  several  weeks  old,  even 
though  they  are  then  performed  for  the  first  time,  always  sug- 
gest the  possibility  that  they  are  a  product  of  training,  although 
in  many  cases  it  seems  more  plausible  to  regard  them  as  nat- 
ural tendencies  which  are  the  outcome  of  simple  maturation. 
The  ability  of  a  baby  to  reach  out  and  grasp  an  object  which 
he  sees,  usually  appears  when  he  is  four  or  five  months  old. 
It  is  uncertain  whether  this  act  is  due  to  the  maturation  of  his 
nervous  system  or  is  the  result  of  trial  and  error  learning. 
Before  this  so-called  eye-hand  coordination  is  attained  he  has 
grasped  many  objects  which  come  in  contact  with  the  palm 
of  his  hand  and  has  fixated  these  objects  with  his  eyes.    The 

l  Watson,  Psychology,  chapters  6  and  7. 


THE  BEHAVIOR  OF  BABIES  93 

question  could  be  decided  only  by  placing  the  child  in  such 
restraint  that  no  experience  would  be  possible  in  casual  grasp- 
ing. If,  on  being  given  his  freedom  at  the  proper  time,  the 
eye-hand  coordination  at  once  occurred,  we  could  assign  it 
with  certainty  to  the  category  of  instinct.  The  suddenness 
with  which  this  and  other  coordinated  movements  occur,  how- 
ever, lends  plausibility  to  the  assumption  that  such  acts  are* 
dependent  upon  late  maturation  and  are  to  some  extent  inde- 
pendent of  training. 

Just  after  a  baby  is  born,  and  when  he  begins  to  breathe, 
a  vocalization  known  as  the  birth  cry  occurs.  This  cry  is 
elicited  by  asphyxia  and  the  customary  slapping.  Yawning 
has  been  observed  five  minutes  after  birth,  and  sneezing  some- 
times occurs  as  soon  as  the  baby  is  born.  Blanton2  describes 
the  "colic  cry"  as  being  high  pitched  and  different  in  this 
respect  from  the  general  crying  due  to  hunger,  pain,  and 
fatigue.  Crying  in  response  to  a  cold  plunge  may  be  inspira- 
tory in  character.  Drawing  down  the  corners  of  the  mouth 
while  crying  has  been  observed  30  minutes  after  delivery,  and 
the  transverse  crease  between  the  eyes  may  occur  at  birth. 
Being  picked  up  may  cause  the  baby  to  cry,  and  a  surgical 
operation  will  at  any  time  cause  this  response. 

Blanton  reports  the  following  sounds  during  the  first 
month :  m,  n,  ng,  h,  w,  r,  y,  ozv  as  in  owl,  ee  as  in  feel,  oo  as  in 
pool,  a  as  in  an,  and  a  as  in  father. 

The  enteric  responses  given  the  first  day  are  swallowing, 
hiccoughing,  regurgitation,  spitting  out,  sucking,  licking,  and 
defecation. 

Binocular  accommodation  and  fixation  of  a  light  are  often 
to  be  observed  during  the  first  hour.  Fixation  is  most  easily 
elicited  when  the  light  is  placed  directly  in  front  of  the  child. 
Blanton  reports  that  the  eyes  of  many  babies  follow  a  slow 
moving  hand  at  birth.  Watson  observed  no  blinking  prior  to 
the  fifty-fifth  day.     The  head  may  be  rotated  toward  the 

2  Blanton,  Behavior  of  the  Human  Infant,  Psychological   Review,  1917,   pages  45G-483. 


94  THE  BEHAVIOR  OF  BABIES 

source  of  light  during  the  first  few  days.  Tears  may  be  pres- 
ent from  birth. 

Smiling  has  been  observed  in  babies  as  young  as  4  days 
and  may  result  from  tickling  on  the  face,  stroking  other  parts 
of  the  body,  rocking,  or  being  turned  on  the  abdomen  across 
the  nurse's  knee. 

In  response  to  sound,  the  child  may  start,  squirm,  or 
awaken  from  sleep  any  time  after  birth.  Blanton  reports 
children  turning  the  head  toward  the  source  of  sound  between 
the  fourth  and  fourteenth  days  when  a  paper  bag  was  rattled. 

If  placed  face  down  upon  a  flat  surface,  the  baby  may 
rotate  the  head  a  half  hour  after  birth.  According  to  Blanton 
practically  all  babies  three  days  of  age  will  raise  the  head  when 
the  face  is  buried  in  a  pillow.  When  held  in  a  sitting  posture 
the  baby  may  hold  its  head  in  equilibrium  after  the  second  or 
third  day. 

Finger  movements  may  be  observed  at  birth,  and  the 
grasping  reflex  is  sufficiently  strong  from  this  time  on  to  make 
it  possible  for  the  infant  to  support  its  body  weight  when  hold- 
ing to  a  rod.  This  response  is  most  energetic  in  the  case  of 
a  crying  child. 

At  any  time  after  birth,  when  the  child  is  dropped  the 
arms  are  thrown  up  toward  the  head.  When  the  head  is  being 
scrubbed  shortly  after  birth  the  interference  of  the  baby's 
hand  sometimes  interrupts  the  process.  Watson,  on  taking 
hold  of  the  nose  of  a  three  day  old  baby,  found  that  the  child's 
hands  almost  immediately  engaged  his  fingers.  Avoidance 
movements  of  the  arms  may  be  elicited  in  very  young  infants 
by  gentle  pricking  of  the  wrist.  Kicking  is  commonly  aroused 
by  the  clamping  and  tying  of  the  umbilical  cord. 

Blanton  found  that  dropping  alcohol  on  either  side  of  the 
abdomen  elicited  a  leg  movement  on  the  side  stimulated.  She 
reports  that  when  the  big  toe  is  pricked  to  secure  a  secpimen 
of  blood  the  other  foot  is  drawn  up  and  pressed  against  the 
ankle  of  the  pricked  side.  Watson  found  that  when  an  infant 


THE  BEHAVIOR  OF  BABIES  95 

at  5  days  of  age  is  pinched  on  the  inner  surface  of  the  knee, 
the  other  heel  will  be  brought  up  to  this  spot. 

Stretching  and  arching  in  response  to  removal  of  clothing 
has  been  observed  on  the  twenty-fifth  day.  Shivering  may 
occur  shortly  after  birth  and  the  toes  may  be  curled  when  the 
feet  are  exposed  to  the  warmth  of  a  fire  when  the  child  is  a  few 
days  old. 

When  suddenly  lowered,  in  addition  to  the  upward  move- 
ment of  the  arms,  there  is  elicited  grasping  and  holding  the 
breath.  Another  coordinated  movement  which  may  occur  dur- 
ing the  first  few  days  is  turning  over  after  being  placed  face 
down.  Creeping  backward  may  occur  during  the  second  week, 
but  the  change  of  position  is  very  slight.  Blanton  records  in 
the  case  of  one  baby  two  hours  old  the  repeated  act  of  placing 
the  hand  in  the  mouth.  The  youth  of  the  child  would  indicate 
this  to  be  an  instinctive  mechanism. 

Watson  found  no  tendency  on  the  part  of  a  baby  of  169 
days  to  wipe  its  hands  when  given  a  ball  of  library  paste.  If 
hand  wiping  is  an  instinctive  response,  which  may  be  doubted, 
it  matures  at  a  later  period.  The  same  experimenter,  contrary 
to  the  description  of  the  recapitulationists,  could  elicit  no 
swimming  movements  from  young  infants. 

Some  of  Watson's  observations  of  emotional  responses 
may  be  stated  here.  Blinking  and  an  upward  movement  of  the 
hands  were  elicited  at  100  days  in  response  to  a  threatening 
gesture.  Crying  followed  loud  sounds  or  the  jerking  of  the 
baby's  blanket.  No  fear  responses  were  given  by  the  165  days 
old  baby  to  the  sight  or  handling  of  a  cat,  a  rabbit,  or  a  pigeon. 
Rage  responses,  consisting  of  stiffening  the  body,  holding  the 
breath,  thrashing  with  arms  and  legs,  and  screaming,  were 
produced  by  hampering  the  infant's  movements  or  by  simply 
holding  the  arms  or  head. 

Conditioned  responses  occur  early  in  infancy,  but  the 
older  observers  did  not  distinguish  carefully  between  habit  and 
instinct  in  reporting  the  behavior  of  babies.    One  of  Watson's 


96  THE  BEHAVIOR  OF  BABIES 

cases  learned  to  cry  in  response  to  the  touch  of  the  lifting  rod 
and  even  to  the  sight  of  the  approaching  experimenter. 

Most  of  the  original  tendencies  mentioned  above  are 
fairly  simple  responses.  As  any  normal  child  grows  older 
we  find  him  creeping,  walking,  balancing  without  support  and 
with  stationary  feet,  climbing,  hitting,  throwing,  running  in 
pursuit  of  moving  objects,  avoiding  obstacles  in  his  path,  and 
making  many  other  movements  which  the  young  of  lower 
animals  make  as  a  result  of  neurological  endowment.  To  what 
extent  these  acts  in  the  human  child  are  instinctive  is  largely 
a  matter  of  surmise.  The  child's  opportunity  for  establishing 
many  of  these  stereoptyped  responses  by  trial  and  error  learn- 
ing is  certainly  great,  and  the  uniformity  of  conditions  under 
which  all  children  live  makes  tenable  the  assumption  that 
learning  is  here  an  important  factor.  Spalding  demonstrated 
that  birds  fly  without  preliminary  trials,  and  that  their  awk- 
ward first  attempts  at  flying  are  due  to  the  immature  condi- 
tion of  an  instinctive  flying  mechanism.  His  experiment  was 
to  confine  one  set  of  birds  so  that  they  could  not  fly  and  to 
leave  unrestrained  a  control  group  of  the  same  age.  When  the 
control  group  had  "learned"  to  fly  successfully  the  confined 
birds  were  liberated  and  were  found  to  fly  at  once  with  all  the 
precision  of  the  others.3 

It  would  be  unjustified  to  infer  by  analogy  that  the  child's 
first  efforts  at  walking  are  similarly  the  responses  of  an  im- 
mature walking  mechanism.  It  has  already  been  pointed  out 
that  man  lacks  in  large  part  the  elaborate  instinctive  tendencies 
of  the  lower  animals.  Spalding's  results,  however,  should  make 
us  cautious  of  denying  in  the  case  of  the  baby  natural  locomo- 
tion tendencies.  There  is  some  evidence  that  these  tendencies 
are  instinctive.  Spontaneous  walking  without  preliminary 
trials  has  been  occasionally  reported  of  babies  under  the  ob- 
servation of  psychologists. 

Balancing  on  the  feet  is  almost  certainly  an  instinctive 
endowment,  just  as  is  balancing  the  head.  Stair  climbing,  and 

3  Preyer,   Mind  of  the  Chiltl,  Parr   1,   page   230.     Spalding,   in  Nature,   Vol.   12,   page   507. 


THE  BEHAVIOR  OF  BABIES  97 

many  other  forms  of  locomotion  involving  the  surmounting  of 
obstacles,  are  in  part  habits. 

In  the  absence  of  experimental  work  we  must  be  content 
with  conjecture  as  to  how  a  child  learns  to  throw.  Grasping 
and  releasing  an  object  are  instinctive,  as  are  also  paddling 
movements  of  the  arms.  The  combination  of  these  movements 
may  result  in  throwing  any  object  which  is  held  in  the  hand. 
The  serial  response  so  established  by  trial  and  error  may  be 
the  beginning  of  a  throwing  habit. 

Skillful  manipulation  of  objects  and  the  stereotyped 
movements  involved  in  transporting  objects  from  place  to 
place  can  not  be  regarded  as  instinctive. 

More  than  95  per  cent  of  adults  are  right-handed.  It  may 
be  asked  whether  this  is  an  acquisition  or  a  natural  tendency. 
Most  children  are  trained  by  their  parents  to  use  the  right 
hand  in  holding  and  manipulating  such  articles  as  cups,  spoons, 
or  pencils.  Doll  reports  that  among  the  feeble-minded  about 
half  are  right-handed  and  half  are  left-handed.4  This,  to- 
gether with  the  facts  that  the  feebleminded  are  characteristic- 
ally apathetic  toward  instruction  and  that  they  often  occur  in 
families  where  but  little  instruction  is  offered,  suggests  the 
possibility  that  dextrality  is  the  result  of  training.  Among 
babies  up  to  the  age  of  three  weeks  Watson  found  no  prefer- 
ential use  of  either  hand  in  supporting  the  body  weight. 

Opposing  the  hypothesis  that  right-handedness  is  wholly 
an  acquisition  is  the  absence  of  any  isolated  society  of  left- 
handed  people.  In  anthropological  museums  a  left-hand 
weapon  is  an  anomaly,  although  the  Australian  boomerang  is 
thrown  with  the  left  hand.  There  is  some  evidence  for  the 
belief  that  among  left-handed  persons  the  regions  of  Broca 
and  Wernicke  are,  contrary  to  the  rule,  commonly  found  in 
the  right  hemisphere.  If  this  is  so,  it  might  argue  for  an 
instinctive  right-  or  left-handedness. 

Original  responses  of  spitting  out,  grimacing,  and  head- 

4  Peterson  and  Rainey,    Iieuinnino"  of  Mind  in  the  New  Born,  in  the  Bulletin  of  the  Lying-in 
Hospital  of  the  City  of  New  York,   1910. 


98  THE  BEHAVIOR  OF  BABIES 

turning  seem  to  follow  gustatory  stimulation  by  bitter  and  sour 
substances.  When  sugar  solution  is  placed  on  the  lips,  sucking 
and  licking  result.  Refusal  to  nurse  when  the  nipple  has  been 
smeared  with  oil  of  amber  or  petroleum  is  reported  by  Kro- 
ner.5 It  is  doubtful  whether  this  is  a  taste,  a  tactile,  or  an  odor 
response.  Peterson  and  Rainey  attribute  grimacing,  sucking 
movements,  and  restlessness  to  olfactory  stimulation. 

Natural  tendencies  of  approach  and  of  avoidance  are  thus 
organized  about  situations  of  direct  vital  importance.  Avoid- 
ance responses  are  provoked  by  noxious  stimuli  and  by  stimuli 
that  are  distinctively  characteristic  of  harmful  situations. 
Instinctive  reactions  to  restraint,  loud  noises,  and  bodily  injury 
have  already  been  described.  Approach  or  quiescence  is  called 
out  by  stimuli  which  are  commonly  associated  with  the  pres- 
ence of  food  or  with  safe  and  beneficial  conditions.  This  am- 
bivalent equipment  gives  direction  to  all  habit  formation,  and 
with  it  the  new  born  infant  is  ready  to  enter  upon  trial  and 
error  learning  with  considerable  security.  No  visual  stimulus, 
unless  intense  enough  to  cause  injury,  will  elicit  original  move- 
ments of  avoidance  or  attack.  A  baby  soon  learns,  however, 
to  retreat,  struggle,  or  cry  at  sight  of  those  objects  whose 
contact  has  on  previous  occasions  aroused  avoidance.  Condi- 
tioned responses  of  this  sort  soon  modify  the  baby's  original 
nature. 

When  instinctive  avoidance  is  unsuccessful  in  freeing  the 
child  from  noxious  stimuli,  movements  of  attack  are  gener- 
ally the  instinctive  result.  Thus  resistance  to  the  intention  of 
others  is  early  developed  and  bad  temper  follows  upon  teasing 
or  upon  the  rough  handling  sometimes  involved  in  dressing, 
bathing,  or  in  any  abrupt  manipulation. 

We  cannot  be  certain  that  responses  other  than  those  of 
orientation,  pupillary  contraction,  eye  closure,  and  facial 
grimace  are  instinctively  made  when  light  stimulates  the  eye. 
Although  endowed  with  but  this  meagre  repertoire  of  light 

5  Peterson  and  Rainey,   see  note  4. 


THE  BEHAVIOR  OF  BABIES  99 

responses,  in  later  life  man's  most  elaborate  behavior  is 
brought  about  by  what  he  sees. 

The  avoidance  movements  of  fear,  the  attack  movements 
of  rage,  and  the  approach  movements  of  love  are  given  to 
visual  stimuli  only  through  the  process  of  conditioning.  We 
must  learn  to  keep  our  distance  from  charged  wires,  danger- 
ous animals,  stoves,  falling  objects,  and  people  who  sneeze. 
We  must  acquire  the  habit  of  striking  out  at  aggressors  who 
have  not  yet  touched  us,  and  to  cry  when  dangerous  objects 
are  seen  approaching.  Without  previous  bodily  contact  pro- 
bably no  sex  responses  would  be  given  to  visual  stimuli. 

With  these  fairly  definite  response  tendencies  a  baby  is 
born  into  an  orderly  world.  He  is  exposed  to  a  systematic  rou- 
tine and  a  fixed  sequence  of  situations.  Above  all,  the  com- 
bination of  stimuli  resident  in  such  objects  as  his  bed,  his 
clothing,  his  tub,  his  mother,  and  his  own  body  is  almost  in- 
variable. The  original  nature  common  to  all  babies,  together 
with  the  inevitable  environment  which  they  all  share,  develops 
similar  habits  in  all  children.  That  all  people  have  not  identi- 
cal habits  is  due  to  slight  individual  differences  in  endowment 
and  to  the  peculiarities  of  the  world  that  each  lives  in.  These 
neurological  and  environmental  differences  are  more  likely  to 
be  noticed  than  the  commonality  of  endowment  and  the  univer- 
sality of  the  world  order,  which  latter  are  so  commonplace  that 
their  importance  is  often  underestimated. 

The  habits  wThich  are  produced  and  called  out  by  common 
situations  which  everyone  experiences,  are  frequently  given 
such  names  as  fighting  instinct,  mating  instinct,  hunting  in- 
stinct, hoarding  instinct,  shelter-seeking  instinct,  maternal 
instinct,  gregarious  instinct,  or  instincts  of  curiosity,  approval, 
scorn,  mastery,  and  submission.  Even  in  the  behavior  of  lower 
animals  the  acts  described  by  these  terms  may  owe  something 
to  learning.  When  performed  by  man  they  are  always 
acquired  reaction  tendencies,  though  we  all  possess  them  by 
virtue  of  our  having  a  common  human  nature  which  is  trained 


100  THE  BEHAVIOR  OF  BABIES 

in  a  common  world.  The  extent  of  man's  capacity  for  form- 
ing conditioned  responses,  which  distinguishes  him  from  lower 
animals,  is  the  outstanding  attribute  of  human  nature. 

Habits  which  men  universally  share  are  obviously  to  be 
distinguished  from  the  private  habits  of  typewriting,  piano 
playing,  vocations,  hobbies,  personal  idiosyncracies  and  the 
like.  There  is  no  adequate  term  for  them  in  psychology.  They 
might  be  called  instinct-habits,  common  action  patterns,  vul- 
garities, primary  acquirements,  or  common  acquisitions,  but 
all  these  terms  are  either  ambiguous  or  cumbersome  and  none 
of  them  is  sufficiently  concise  to  describe  so  important  a  class 
of  acts.  For  lack  of  a  better  word  we  shall  employ  the  term 
coenotropes  to  describe  universal  modes  of  response  which  are 
the  product  of  original  nature  and  commonly  shared  environ- 
ment. Further  experiment  may  discover  the  integration  of 
these  coenotropes  to  be  more  dependent  upon  the  slow  matura- 
tion of  innate  nervous  structures  than  we  now  have  reason  to 
suppose. 

The  attainment  of  coenotropes  and  of  certain  instincts 
does  not  occur  until  some  time  after  birth.  If  a  chick  never  sees 
a  hen  until  it  is  ten  days  old  it  will  not  follow  her.  James  argues 
from  this,  and  from  similar  examples,  that  "many  instincts 
ripen  at  a  certain  age  and  then  fade  away."6  He  cites 
Spalding's  account  of  a  chick  which  was  kept  away  from  its 
mother  for  the  first  ten  days  and  then,  being  replaced,  showed 
no  tendency  to  follow  the  hen.  It  did,  however,  follow  any 
person  of  whom  it  caught  sight,  having  acquired  this  habit 
during  the  first  few  days.  This  fact  should  not  be  interpreted 
to  mean  that  an  instinct  had  faded  away.  There  is,  of  course, 
no  following-the-hen  instinct.  The  young  chick  will  follow 
anything,  a  handkerchief  dragged  along  the  floor,  or  a  re- 
treating man,  dog,  or  hen. 

The  young  and  inexperienced  chick  follows  either  men 
or  hen  to  the  disregard  of  stationary  objects.  The  original 

6  James,   Principles  of  Psychology,  Vol.    2,   page   31KS. 


THE  BEHAVIOR  OF  BABIES  101 

tendency  to  follow  is  probably  stronger  than  the  original  ten- 
dency to  approach  anything  which  is  at  rest.  If  the  threshold 
for  following  a  man  has  been  lowered  by  practice,  even 
though  the  tendency  to  approach  the  still  object  is  similarly 
lowered,  man-following  may  prevail  over  the  tendency  to  ap- 
proach the  motionless  object.  As  no  practice  has  lowered  the 
threshold  of  the  hen-following  response,  the  chick  may  well 
disregard  the  hen  and  busy  itself  with  other  stimuli  the 
responses  to  which  have  been  well  practised. 

The  response  tendencies  present  in  the  new  born,  being 
uninhibited  by  incompatible  habits,  may  become  attached  to 
any  one  of  a  multitude  of  objects.  Distracting  habits,  once 
formed,  however,  inhibit  the  relatively  sluggish  instinctive 
response  to  a  novel  object,  although  this  response  might  have 
been  given  before  such  incompatible  habits  stood  in  the  way. 

The  oft  rehearsed  man-following  habit  of  Spalding's 
chick  was  well  enough  grounded  to  compete  successfully  with 
the  tendencies  to  scratch,  peck,  or  make  off  toward  moving 
bugs.  There  being  no  hen-following  habit,  we  may  suppose 
that  the  hen,  when  later  introduced,  was  merely  powerless  to 
compete  for  the  chick's  attention  in  the  face  of  these  distrac- 
tions. This  seems  more  reasonable  than  the  hypothesis  of 
transiency  of  instinct. 

As  with  the  chick,  so  with  the  child.  At  first  one  wet- 
nurse  will  be  accepted  about  as  readily  as  another,  but  later, 
when  the  infant  has  formed  the  nursing  habit  toward  his 
mother,  she  alone  is  able  to  elicit  energetic  and  contented  suck- 
ling. Something  in  his  mouth  is  not  the  only  stimulus  which 
calls  forth  the  nursing  response  in  the  practised  baby.  His 
mother's  way  of  holding  and  talking  to  him,  the  shape  of  her 
breast,  and  her  general  appearance  are  all  conditioning  stim- 
uli which  facilitate  the  child's  nursing.  In  the  case  of  the 
strange  nurse,  the  absence  of  these  conditioning  stimuli  per- 
mits the  success  of  rival  movements  of  resistance  and  crying 
which  tend  to  follow  manipulation.     Such  movements  are  in- 


102  THE  BEHAVIOR  OF  BABIES 

hibited  by  the  behavior  called  out  by  the  mother.  Once  the 
movements  of  resistance  and  crying  have  been  elicited  by  the 
strange  nurse,  the  characteristics  in  which  she  differs  from 
the  mother  condition  these  movements,  so  that  the  baby  may 
struggle  in  her  arms  the  next  time,  unless  she  has  succeeded 
in  getting  him  to  nurse  on  the  first  occasion.  We  have  no 
ground  for  supposing  that  mere  strangeness  causes  resistance, 
except  in  so  far  as  a  strange  situation  may  have  the  effect  of 
breaking  up  an  habitual  response  series. 

Instincts  ripen  but  do  they  fade  ?  With  his  law  of  trans- 
iency of  instinct  in  mind,  James  says,  "There  is  a  happy 
moment  for  fixing  skill  in  drawing,  for  making  boys  collectors 
in  natural  history,  and  presently  dissectors  and  botanists ;  then 
for  initiating  them  into  the  harmonies  of  mechanics  and  the 
wonders  of  physical  and  chemical  law."  There  is  certainly  a 
"happy  moment"  for  teaching  a  child  any  habit.  This,  how- 
ever, is  probably  not  a  "nascent  period"  but  rather  a  time 
before  antagonistic,  incompatible,  or  distracting  habits  have 
been  formed. 


CHAPTER  5 
PERCEPTION 

A  single  object,  such  as  a  banana,  may  furnish  stimuli  to 
eyes,  ears,  nose,  tongue,  skin,  muscles,  or  to  sense  organs  in 
the  enteric  tract,  but  not  all  these  stimuli  affect  us  at  the  same 
time. 

A  watch  lies  on  the  table.  On  receiving  visual  stimuli 
from  a  portion  of  the  surface  of  the  watch,  we  may  pick  it  up 
and  receive  cutaneous  and  kinaesthetic  stimuli,  turn  it  over 
and  see  the  other  side,  or  carry  it  to  the  ear  and  hear  it  tick. 
It  is  in  the  nature  of  objects  that  they  embody  this  assemblage 
of  diverse  stimuli. 

In  the  beginning,  our  responses  to  watches  or  to  bananas 
are  merely  reflexes  to  the  separate  stimuli  which  those  objects 
furnish.  While  we  respond  to  contact  with  the  object  other 
stimuli  from  the  same  object  frequently  act  upon  us.  While 
seeing  an  object  we  may  also  smell  it.  While  smelling  it  we 
may  also  hear  it.  Thus,  each  stimulus  may  finally  call  forth, 
by  conditioning,  any  of.  the  responses  which  any  of  the  other 
stimuli  would  naturally  provoke.  In  this  sense  we  may  say  that 
an  adult  responds  to  an  object  as  a  whole.  After  experiencing 
together  the  various  stimuli  emanating  from  an  object,  we 
react  in  a  way  which  anticipates  stimuli  that  the  object  is 
likely  soon  to  furnish. 

A  baby  finally  learns  to  avoid  bodily  contact  with  fire, 
barking  dogs,  whirling  machinery,  and  wet  paint  merely  upon 
seeing  them  at  a  distance,  although  the  visual  appearance  of 
these  objects  calls  forth  no  original  avoidance  responses.  He 
learns  to  smile  at  sight  of  his  mother  who  has  cuddled  him, 
to  cry  at  the  touch  of  a  lifting  rod,  and  to  support  his  nursing 
bottle  with  his  two  hands  when  the  nipple  is  placed  in  his 
month.    All  these  acts  are  conditioned  responses  to  substituted 

(103) 


104  PERCEPTION 

stimuli,  and  the  formation  of  such  conditioned  responses  con- 
stitutes acquaintance  with  the  objects. 

When  by  this  process  of  conditioning  any  stimulus  from 
the  object  furnishes  a  cue  for  the  early  occurrence  of  re- 
sponses which  were  originally  given  only  as  the  result  of 
further  acquaintance,  the  baby  is  said  to  perceive  the  object. 

It  is  in  the  process  of  manipulating  or  merely  observing 
a  thing  that  the  baby  receives  simultaneously  the  various 
stimuli  which  are  resident  in  it.  His  response  to  any  one  of 
these  stimuli  may  then  become  attached  to  any  other.  In  his 
behavior  towards  any  object  such  as  a  chair,  a  pin,  a  stick  of 
candy,  or  his  own  hand,  some  of  these  responses  tend  to  be- 
come dominant  and  are  attached  by  conditioning  to  many  of 
the  minor  stimuli  with  which  the  object  provides  the  baby. 

Thus  objects  come  to  "look"  heavy,  hot,  smooth,  wet,  or 
soft.  Things  "sound"  large,  thin,  distant,  or  as  though  in 
rapid  motion.    By  touch  or  odor  objects  may  be  identified. 

The  stimuli  offered  by  an  object  may  be  materially  altered 
as  a  result  of  the  baby's  intervention,  locomotion,  or  orienta- 
tion. If  he  tears  or  crumples  paper  it  makes  a  noise  and  takes 
on  a  different  visual  appearance.  If  he  grasps  a  pin  it  may 
prick  his  finger.  If  he  inverts  the  inkstand  the  ink  is  spilled. 
If  he  pushes  a  tumbler  off  the  table  it  falls  and  crashes.  If  he 
releases  his  rattle  it  may  tumble  off  the  bed.  These  changes 
in  the  form  or  the  position  of  the  objects  occasion  new  re- 
sponses, which  by  conditioning  are  later  called  out  by  any 
cue  which  the  object  furnishes. 

A  part  of  our  environment  is  always  changing.  We  must 
learn  to  look  out  for  danger  and  to  take  advantage  of  fortunate 
opportunities.  Moving  objects  alter  the  stimulation  they  give 
us  although  we  remain  quiet.  Animals,  guns,  matches,  and 
engines  have  their  own  peculiar  ways  of  behaving  in  response 
to  our  manipulations,  and  the  baby's  growing  perception  of 
such  objects  as  these  includes  many  anticipating  responses 
dependent  on  past  encounters.    A  firecracker  never  looks  the 


PERCEPTION  105 

same  to  the  baby  after  one  has  exploded  in  his  fingers.  The 
baby  ceases  to  use  the  cat's  tail  as  a  handle  after  he  has  once 
picked  up  an  aggressive  cat  in  this  way.  He  learns  to  bounce 
his  ball,  to  tease  his  parents,  and  to  coerce  younger  children. 
When  this  learning  has  occurred  we  say  that  he  perceives  the 
ball  as  something  which  bounces,  parents  and  companions  as 
individuals  who  may  be  imposed  upon. 

Situations  recur  time  after  time  in  orderly  grouping  and 
sequence.  The  frequent  reiteration  of  responses  to  these  re- 
curring events  enables  us  to  perceive  a  situation  as  one  which  is 
about  to  be  followed  by  its  familiar  consequences.  Our  abil- 
ity to  do  this  is  dependent  upon  the  overlapping  of  the  parts 
of  situations  which  permits  the  formation  of  conditioned  re- 
sponses. The  change  from  one  situation  to  the  next  is  always 
a  partial  change,  and  any  two  successive  events  have  elements 
in  common. 

There  is  then,  on  the  one  hand,  perception  of  objects  with 
their  groupings  of  available  stimuli,  and,  on  the  other  hand, 
the  perception  of  events  with  their  temporal  sequence  of  stim- 
uli. Perceptions  can  not  be  sharply  divided  into  these  two 
classes,  but  any  perception  may  be  characterized  as  a  percep- 
tion chiefly  of  things  or  chiefly  of  occurrences. 

Perception  is  always  a  reaction  tendency  more  or  less 
completely  expressed.  When  less  complete,  the  expression  is 
often  limited  to  an  orientation  of  receptors  and  effectors,  but 
the  neurological  changes  which  go  unobserved  are  often  far 
reaching.  Thus  a  perception  which  is  apparently  limited  to 
orientation  may  be  a  very  extensive  process  in  the  central 
nervous  system.  As  a  result  of  our  observing  a  thing,  the 
thresholds  of  many  other  responses  are  raised  or  lowered. 
When  we  glance  at  the  articles  in  a  shop  window  or  hear  it  said 
that  the  bank  closes  today  at  twelve  o'clock,  delayed  reactions 
are  initiated  which  are  brought  to  pass  only  upon  further  stim- 
ulation, or  in  conjunction  with  other  responses  not  yet  aroused. 
In  this  way  reaction  tendencies  are  altered  by  stimuli  which 


106  PERCEPTION 

are  merely  observed  and  to  which  at  the  time  we  give  no  overt 
response.  We  may  sit  inertly  on  the  shore  and  watch  people 
swimming,  and  it  may  seem  to  an  onlooker  that  but  few  re- 
sponses are  involved  in  our  perception.  The  next  day,  how- 
ever, we  bring  a  swimming  suit  to  the  beach  and  it  is  then 
evident  that  many  changes  occurred  in  our  nervous  structure 
as  a  result  of  the  situation  which,  when  operating,  was  only 
"observed."  An  immediate  overt  reaction  to  objects  is  much 
less  frequent  than  is  the  act  of  observation. 

PERCEPTION  AND  SPEECH 

An  object  may  at  different  times  prompt  us  to  different 
perceptions.  Perceptions  involving  a  verbal  response  consti- 
tute a  most  important  class,  and  such  responses  often  serve  to 
drain  much  of  the  enegy  that  situations  arouse.  Our  interest 
in  a  distant  object  is  often  terminated  as  soon  as  we  are  able 
to  name  it. 

The  expression  of  word  perceptions  is  usually  subvocal. 
Verbal  symbols  serve  as  cues  for  many  subsequent  acts.  An 
object  named  is  often  an  object  with  which  we  are  in  a  better 
position  to  deal,  because  much  appropriate  behavior  is  at- 
tached to  words  by  conditioning.  Once  we  have  said  "Good 
bye"  there  is  little  to  do  but  to  go  away.  Before  we  call  a  man 
a  thief  we  are  less  aggressive  in  our  antagonism  toward  him 
than  we  are  after  the  word  has  been  used. 

The  subvocal  expression  of  word  response  tendencies  is 
an  essential  part  of  thinking.  Perception  in  verbal  terms 
initiates  new  word  reactions  and  by  the  series  of  word  re- 
sponses our  conduct  is  guided. 

Such  subvocal  responses  consist  in  slight  contraction  of 
muscles  which,  if  stimulation  were  more  intense  or  inhibi- 
tions were  absent,  would  result  in  actual  speech.  We  may 
often  see  fellow  passengers  on  the  streetcar  moving  their  lips 
in  a  manner  appropriate  to  the  words  which  they  are  reading, 
and  we  can  readily  observe  slight  movements  of  our  own  vocal 


PERCEPTION  107 

apparatus  which  are  minimal  movements  of  speech,  even 
though  these  could  not  be  detected  by  others. 

Such  minimal  responses  are  not  confined  to  speech.  Many 
of  the  onlookers  at  a  boxing  contest  may  be  seen  to  follow  the 
contest  with  minimal  defense  and  attack  movements,  and  in 
the  theatre  audience  there  are  many  who  shrug  their  shoulders 
with  the  heroine  and  become  stern  when  the  villain  is  confront- 
ed by  the  hero.  These  movements  are  sometimes  mimetic,  but 
that  they  are  not  regularly  so  is  shown  by  the  fact  that  they 
often  anticipate  the  movement  of  the  boxer  or  of  the  actor 
and  are  the  onlooker's  response  to  the  antagonist's  threatened 
blow  or  to  the  villain's  advances. 

These  minimal  movements  constitute  in  part  the  percep- 
tion of  situations,  and,  since  they  themselves  offer  proprio- 
ceptive stimulation,  such  movements  may  be  the  cues  for 
further  responses.  The  clenched  fist  as  well  as  the  muttered 
epithet  plays  a  part  in  determining  subsequent  action. 

Talking  is  a  serial  response.  Many  of  our  sentences  are 
faithfully  reproduced  habits  which  have  been  uttered  in  the 
same  form  hundreds  of  times.  These  stereotyped  sentences  are 
often  imitation  of  other  people's  speech.  In  spite  of  stereo- 
typisms,  we  frequently  use  a  novel  combination  of  words.  This 
is  made  possible  by  the  fact  that  any  word,  when  spoken,  is  a 
stimulus  which  arouses  a  number  of  word  reaction  tendencies, 
because  nearly  any  word  has  in  previous  speech  been  followed 
now  by  one  word  and  now  by  another.  Although  various  se- 
quences of  words  are  available,  the  response  thresholds  at  the 
moment  determine  what  sequence  shall  occur. 

When  we  use  the  word  "abate"  there  is  little  doubt  but 
that  this  will  be  followed  by  the  word,  "nuisance."  But  such 
words  as  "eat",  "carry",  "push",  or  "find"  have  in  the  past 
been  followed  by  so  great  a  variety  of  word  responses  that  it 
is  hard  to  predict  which  of  the  reaction  tendencies  present  will 
prevail. 

The  low  threshold  of  the  word  which  does  prevail  is 


108  PERCEPTION 

determined  by  many  things.  First  of  all  there  is  the  influence 
of  words  uttered  shortly  before  by  either  speaker  or  listener. 
Many  of  the  words  we  use  when  talking  about  football  have 
been  used  on  previous  occasions  after  the  term  "football"  has 
been  introduced. 

An  intelligent  person  in  good  health  holds  to  the  topic 
of  conversation.  One  of  the  symptoms  in  insanity  is  an  un- 
directed verbosity  in  which  the  tendency  to  adhere  to  the 
topic  of  conversation  is  lost,  and  in  which  the  words  occur 
without  regard  to  context.  This  sort  of  speech  has  been  well 
called  "word  salad".  It  is  often  approximated  by  simple- 
minded  and  exciteable  people. 

In  addition  to  the  influence  of  verbal  context  there  is  the 
influence  of  non-verbal  situations  in  determining  our  choice 
of  words.  The  facial  expression  of  our  hearer,  the  fact  that 
he  is  a  man  rather  than  a  woman,  being  in  another's  house 
rather  than  in  our  own,  and  having  a  good  appetite  instead 
of  having  just  satisfied  it,  are  matters  which  determine  the 
words  we  say. 

Among  the  topics  most  tenaciously  adhered  to  in  conver- 
sation are  diet,  romance,  and  adventure.  The  drive  toward 
this  form  of  conversation  is  provided  by  the  visceral  organiza- 
tion of  man  and  needs  but  little  stimulation  from  external 
conditions. 

Most  important  of  all  in  determining  the  form  of  our  sen- 
tences is  the  previous  non-verbal  perception  of  the  objects  or 
of  the  events  which  we  discuss.  Past  events  dictate  the  words 
which  we  use  in  their  description,  as  these  words  are  in  part 
delayed  responses  to  the  described  events. 

The  internal  emotional  responses  play  an  important  role  in 
perception.  Just  as  things  may  "look"  hard,  so  they  may 
'look"  dangerous,  disgusting,  beautiful,  or  annoying.  If  the 
response  threshold  is  high,  or  if  the  provocation  is  slight,  the 
expression  of  the  emotional  response  tendency  may  go  no 
farther  than  these  internal  changes.    As  a  result  of  stronger 


PERCEPTION  109 

stimulation  and  reenforcement,  overt  emotional  responses 
may  result. 

The  form  of  any  perception  is  determined  in  part  by  the 
combination  of  stimuli  which  affects  the  sense  organs  at  the 
time,  and  in  part  by  the  conditioned  responses  which  the 
individual  has  previously  associated  with  these  stimuli.  The 
threshold  of  these  conditioned  responses  varies  in  a  single 
individual  according  to  the  recency  with  which  the  responses 
have  been  performed,  and  according  to  the  nature  of  the 
behavior  in  which  he  has  just  been  engaged.  The  alignment 
of  pieces  on  a  chess  board  is  perceived  most  thoroughly  by  a 
player  who  is  in  practice.  A  page  of  Virgil  may  be  almost 
meaningless  to  a  person  who  has  for  years  neglected  his  Latin. 
Such  a  recent  experience  as  reading  a  detective  story  may  low- 
er our  threshold  of  perception  of  burglars.  Having  run  out  of 
gasoline  the  day  before  lowers  the  threshold  of  perception  of 
the  indicator  of  the  gas  tank.  After  an  accident  on  the  road 
the  driver's  perception  of  traffic  is  changed. 

Due  to  the  dependence  of  perception  on  habit,  the  same 
combination  of  stimuli  will  be  perceived  differently  by  two 
persons.  The  tea  taster's  perception  of  tea,  the  florist's  per- 
ception of  roses,  the  fancier's  perception  of  dogs,  and  the  en- 
tomologist's perception  of  bugs,  differ  from  the  corresponding 
perceptions  of  untrained  persons.  Each  of  us  has  his  private 
equipment  of  habit  and  perceives  any  situation  accordingly. 

Because  response  thresholds  vary  from  time  to  time,  a 
combination  of  stimuli  may  be  perceived  now  in  one  way  and 
now  in  another.  The  words  "time  flies"  may  be  perceived  as 
a  statement  that  time  is  fleeting  or  as  a  request  to  determine 
the  rapidity  with  which  flies  fly.  The  staircase  (Figure  25) 
may  be  perceived  as  a  flight  of  steps  seen  either  from  above  or 
below.  Stimuli  which  may  lead  to  either  of  two  radically 
different  perceptions  ars  called  equivocal  stimuli.  Where  two 
diverse  situations  have  several  elements  in  common,  these  sev- 


110 


PERCEPTION 


Figure  25 — Staircase  figure.     This  may  be  seen  as  a  flight  of  stairs  viewed  from 
above,  or  as  a  flight  viewed  from  below. 

eral  elements  occurring  alone  as  stimuli  may  lead  to  a  percep- 
tion of  either  situation. 

Equivocal  stimuli  often  give  rise  to  false  perceptions 
which  may  be  rectified  by  further  acquaintance  with  the  sit- 
uation. Such  a  false  perception  is  called  an  illusion.  Reacting 
to  a  piece  of  tin  foil  seen  on  the  street  as  though  it  were  a 
coin,  responding  to  a  bit  of  floating  dust  in  the  air  as  though 
it  were  a  house  moth,  running  away  from  the  sound  of  a  fall- 
ing object  in  the  woods  as  though  it  were  a  wild  animal, 
appropriating  another  person's  umbrella  under  the  impression 
that  it  is  one's  own,  are  all  examples  of  illusion. 

An  hallucination  is  a  response  tendency,  not  initiated  by 
sensory  stimuli,  which  follows  a  sensory  impulse  originating  in 


PERCEPTION 


111 


some  part  of  the  nervous  system.  It  is  often  the  result  of 
degenerative  processes  accompanying  nervous  disease,  but 
frequently  occurs  in  healthy  individuals.  All  hallucinations 
conform  to  reaction  tendencies  of  low  threshold.  The  insane 
patient  who  reports  that  he  hears  voices  warning  him  of  the 
treachery  of  an  acquaintance  must  previously  have  acquired 
reaction  tendencies  of  suspicion  toward  the  person  in  question. 
Changes  in  the  sense  organs  themselves,  incident  upon 
circulation  and  upon  metabolism  in  general,  provide  for  the 
normal  individual  sufficient  sensory  cues  for  hallucinations  of 
a  simple  sort.  This  is  most  likely  to  occur  when  he  is  in  a  half 
waking  state  and  partially  isolated  from  sensory  stimuli.  It  is 
of  common  occurrence  for  a  person  to  report  that  his  name 
has  been  spoken  just  as  he  is  about  to  go  to  sleep.  Visions 
are  most  frequently  seen  in  the  dim  light  of  bed  rooms. 


Figure  26 — The  face  which  is   perceived   as  nearest   the   observer  may  also  be 
perceived  as  the  most  distant. 


Our  perceptions  are  determined  not  only  by  the  habits 
we  have  acquired  but  also  by  the  kind  and  by  the  intensity  of 
the  sensory  stimulation  to  which  we  happen  to  be  exposed. 
vStimuli  may  occur  in  combinations  of  practically  unlimited 
diversity  and  no  two  situations  are  ever  wholly  identical.  As 
two  situations,  but  slightly  different,  may  cause  two  very  dif- 
ferent perceptions,  the  number  of  possible  perceptions  is 
almost  unlimited. 


112  PERCEPTION 

Compromise;  Responses  in  Perception 

Compromise  responses  have  already  been  described.  As 
we  walk  through  the  woods  the  direction  which  our  footsteps 
take  is  a  compromise  of  the  many  orientation  tendencies  which 
are  aroused  by  rocks,  trees,  and  the  contour  of  the  ground. 
The  course  of  a  bird  flying  through  the  forest  is  determined 
by  the  visual  stimuli  from  all  the  obstacles  which  it  must 
avoid.  There  seldom  occurs  an  isolated  response.  Most  re- 
sponses are  somewhat  distorted  by  the  total  behavior  of  the 
moment. 

Objects  and  events  are  never  perceived  independent  of 
their  settings.  My  dollar  is  one  thing  and  his  dollar  is  quite 
another.  Food  at  meal  time  furnishes  a  perception  very  dif- 
ferent from  that  of  food  after  dinner.  Soap  experienced 
together  with  towels  and  water,  and  soap  seen  on  a  druggists 
counter  are  not  perceived  merely  as  soap.  A  word  has  complete 
meaning  only  in  its  context,  and  we  perceive  short  sentences 
as  wholes  and  not  as  lists  of  words. 

Man  is  undoubtedly  of  all  animals  the  best  endowed  with 
neurological  mechanisms  for  compromise  responses.  When 
an  unfamiliar  combination  of  stimuli  produces  a  resultant 
reaction,  the  act  so  integrated  may  become  a  response  habit. 
In  this  way  perceptions  shift  their  content  and  grow  in  fitness 
and  complexity  as  a  result  of  the  successive  occurrence  of 
slightly  different  assemblages  of  stimuli.  Each  unusual  oc- 
currence in  a  situation  leaves  behind  it  a  trace  of  compromise 
which  becomes  a  part  of  later  perceptions  of  events  somewhat 
the  same. 

Perceptions  From  Simultaneous  Stimuli 

There  is  no  one  sense  organ  in  the  skin  or  muscles  by 
which  we  perceive  things  as  hard,  soft,  rough,  smooth,  wet, 
dry,  greasy,  or  sticky.  In  comparison  with  a  soft  object,  a  hard 
object,  when  pressed  upon,  gives  more  intense  stimulation  to 
touch  and  pain  organs  and  stimulates  a  smaller  area  of  the 


PERCEPTION  113 

skin.  The  muscles  involved  when  we  lean  upon  such  an  object, 
or  when  we  grasp  it,  are  often  under  greater  tension  than  if 
the  object  were  soft. 

When  we  draw  our  finger  along  a  surface  which  intermit- 
tently stimulates  the  sense  organs  of  touch,  we  say  that  it  is 
rough.  When  the  movement  stimulates  the  same  organs  in  the 
muscles,  but  when  the  stimulation  of  the  sense  organs  of  touch 
is  sustained  and  not  intermittent,  we  call   the  surface  smooth. 

Perception  of  wetness  results  from  the  stimulation  of 
cold  organs  along  with  the  stimulation  involved  in  the  percep- 
tion of  smoothness.  The  perception  of  greasiness  requires  the 
absence  of  the  fine  vibration  of  the  skin  which  is  characteristic 
of  drawing  the  hand  over  a  surface  free  from  grease.  A  silver 
spoon  always  feels  more  greasy  than  a  varnished  table  top 
because  the  polished  metal  surface  offers  less  friction.  Objects 
seem  sticky  when  on  releasing  them  the  skin  adheres  some- 
what to  the  objects  and  is  displaced  outwardly.  The  percep- 
tion of  tickling  necessitates  the  contraction  of  muscles,  espec- 
ially those  adjacent  to  the  area  stimulated,  and  always  contains 
an  emotional  component. 

The  identification  of  objects  by  skin  contact  and  manipu- 
lation alone,  is  called  stereognosis.  If  we  reach  behind  a  screen 
and  feel  an  object  we  can  usually  tell  what  it  is.  A  watch  is 
colder  and  heavier  than  a  pencil  .  The  surfaces  of  the  two 
objects  when  rubbed  afford  different  stimulation  to  sense  or- 
gans in  the  skin  and  muscles.  As  the  finger  follows  the 
contours,  the  position  and  movement  of  muscles  and  joints 
affords  a  characteristic  stimulation.  A  lack  of  resistance  in 
the  loose  parts  of  the  watch  and  the  pliability  of  the  rubber 
end  of  the  pencil  furnish  sensory  cues  to  the  respective  per- 
ceptions. 

Space  Perception 

The  perception  of  distance  or  depth,  and  space  perception 
in  general,  consist  either  of  such  responses  as  saying,  "That 
house  is  about  a  mile  away,"  or  "This  table  is  four  feet  long," 


114  PERCEPTION 

or  of  such  responses  as  throwing  a  stone  at  a  mark,  jumping 
from  one  spot  to  another,  setting  out  to  walk  to  a  certain  ob- 
jective, reaching  for  an  object  near  at  hand,  or  sitting  down 
on  a  chair  which  seems  appropriately  placed,  or  of  such  re- 
sponses as  inhibiting  any  overt  reaction,  or  giving  attention  to 
objects  or  turning  away  from  them  according  as  their  position 
causes  one  sort  of  stimulation  or  another. 

Visual  Space  Perception 

As  a  stimulating  object  changes  its  distance  from  the  eye 
there  is  a  change  in  the  nature  of  its  stimulation  and  a  change 
in  the  character  of  the  responses  which  are  instinctively  given. 
Visual  perception  of  distance  or  depth  depends  ultimately  upon 
these  two  facts.  We  shall  consider  first  the  instinctive  re- 
sponses of  fixation,  binocular  accommodation,  and  monocular 
accommodation. 

When  a  spot  of  light  falls  upon  any  part  of  the  retina 
other  than  the  fovea  there  is  an  instinctive  tendency  so  to  move 
the  eyeball,  and  possibly  the  head  as  well,  that  the  light  shall 
be  brought  to  bear  upon  the  fovea.  This  response  is  called 
fixation.  It  is  effected  by  the  contraction  of  muscles  external 
to  the  eyeball.  These  consist  of  the  four  recti  muscles  and  the 
two  oblique  muscles  of  each  eye.  (Figure  2.)  When  the  same 
object  stimulates  both  eyes,  each  eye  tends  to  fixate.  This 
double  fixation  is  called  binocular  accommodation.  (See  Fig- 
ure 4. ) 

A  straight  line  extending  outward  from  the  center  of  the 
fovea  and  passing  through  the  center  of  the  lens  is  called  the 
line  of  vision.  When  binocular  accommodation  occurs  for  a 
distant  object  the  lines  of  vision  of  the  two  eyes  are  practic- 
ally parallel.  When  we  look  at  a  near  object  these  lines  of 
vision  form  a  greater  angle.  The  degree  of  convergenc  in- 
creases with  the  nearness  of  the  stimulating  object  and  pro- 
duces muscle  strain.  This  muscle  strain  affords  movement- 
produced  stimuli  of  varying  degrees  of  intensity.     The  in- 


PERCEPTION  115 

tensity  and  the  distribution  of  this  stimulation  in  the  external 
eye  muscles  is  one  of  the  sensory  cues  to  the  perception  of 
distance. 

In  order  that  the  image  of  a  near  object  may  be  clearly 
focused  on  the  retina,  the  ciliary  muscle  and  the  iris  muscle 
must  be  contracted  (see  the  description  of  the  eye  in  Chapter 
1 ) .  The  contraction  necessary  to  accomplish  this  clearness  of 
focus  is  called  monocular  accommodation.  The  eye  at  rest 
is  accommodated  for  far  vision.  The  nearer  the  object  the 
greater  is  the  contraction  in  the  circular  fibres  of  the  ciliary 
and  the  iris  muscles,  and  the  greater  is  the  stimulation  to  the 
sense  organs  which  are  in  these  muscles  and  in  their  attach- 
ments. This  varying  stimulation  serves  as  another  sensory  cue 
to  the  visual  perception  of  distance.  The  stimulus  which 
effects  these  instinctive  movements  of  monocular  accommoda- 
tion is  a  blurred  image.  It  is  probable  that  the  stimuli  derived 
from  movements  of  binocular  accommodation  also  produce 
instinctive  monocular  adjustment. 

Along  with  the  varying  degree  of  remoteness  of  an  object 
there  go  changes  of  stimulation  other  than  those  which  cause 
instinctive  binocular  and  monocular  accommodation.  The 
nearer  an  object,  the  larger  is  its  retinal  image.  This  is  a 
sensory  cue  for  perceiving  the  distance  of  all  objects  of  famil- 
iar pattern.  As  all  the  one  cent  pieces  which  we  have  ever 
seen  have  been  uniformly  about  three  quarters  of  an  inch  in 
diameter,  we  have  developed  through  learning  different  re- 
sponses of  approaching  and  reaching  for  pennies  according  to 
the  size  of  the  image  they  cast  on  the  retina.  As  a  tuft  of 
cotton  has  no  uniform  size,  the  size  of  the  retinal  image  which 
it  casts  is  not  very  suggestive  of  its  distance. 

Near  objects  show  a  clearness  of  detail  and  a  differentia- 
tion of  shadows  not  seen  in  objects  which  are  far  away.  This 
difference  in  stimulating  effect  we  learn  to  interpret  percept- 
ually by  appropriate  responses.  The  indistinctness  of  things 
far  away  is  due  mainly  to  articles  in  the  intervening  atmo- 


116 


PERCEPTION 


sphere.  In  the  clear  air  of  Colorado  distant  mountains  look 
deceptively  near.  Trees  seen  through  a  fog  look  larger  than 
they  really  are  because,  being  indistinct,  they  are  wrongly  per- 
ceived as  farther  away.  Being  perceived  as  farther  away  they 
are  consequently  responded  to  as  though  they  were  larger 
trees,  for  larger  trees  farther  away  would  cast  visual  images 
of  the  size  which  the  eye  receives.  This  effect  is  utilized  in  the 
illusion  of  distance  which  is  secured  on  the  stage  by  interpos- 
ing a  fish  net  between  the  back  drop  and  the  audience. 

Far  away  objects  have  a  blue  appearance  due  to  the  polar- 
ization of  sunlight  by  atmospheric  particles,  and  this  provides 
another  sensory  cue  for  perception  of  depth. 

Farther  objects  may  be  partially  obscured  by  nearer  objects, 
and  when  so  seen  are  perceived  as  more  remote  (See  Figure 
27).  Due  to  the  fact  that  most  things  extend  upward  from  the 
ground,  distant  objects  are  ordinarily  seen  over  the  tops  of  ob- 
jects near  at  hand.  Thus  the  objects  higher  in  the  field  of  vis- 
ion are  likely   to  seem  the  more  remote.  (See  Figure  28). 


Figure  27 — The  pear  is  perceived  as  behind  the  apple  because  it  is  partially  hidden 
by  the  apple. 


Figure  28 — Objects  higher  in  the  field  of  vision  tend  to  be  perceived  as  more 
distant. 


PERCEPTION  117 

If  a  far  object  is  fixated  and  the  head  is  moved  from  side 
to  side,  intervening  objects  in  the  field  of  vision  appear  to  move 
in  a  direction  opposite  to  that  of  the  head  movement.  If  a 
near  object  is  fixated,  movement  of  the  head  is  accompanied  by 
the  apparent  movement  of  more  distant  objects  in  the  same 
direction.  When  the  eye  is  at  rest  the  retinal  image  of  an  ob- 
ject passing  in  the  foreground  shifts  more  rapidly  than  that 
of  the  object  moving  at  the  same  speed  in  the  distance. 

When  walking  or  when  riding  in  a  train  the  fixation  of 
near  objects  in  the  landscape  must  be  accomplished  by  more 
rapid  eye  movements  than  the  fixation  of  distant  objects.  All 
these  differences  of  stimulation  serve  as  sensory  cues  to  the 
perception  of  depth. 

An  object  seen  both  with  the  right  eye  and  with  the  left 
eye  is  seen  from  the  two  different  positions,  so  that  each  eye 
views  a  different  part  of  the  object's  surface.  Unless  it  is  bila- 
terally symmetrical  and  of  a  certain  regular  surface  without 
shadows,  the  images  which  it  casts  upon  the  two  retinae  will  be 
dissimilar.  The  nearer  an  object  is  to  the  eye,  and  the  greater 
the  consequent  binocular  convergence,  the  more  dissimilar  are 
the  two  retinal  images.  Not  only  are  the  two  images  which 
are  cast  by  the  same  object  different,  but  these  images  are 
commonly  seen  by  each  eye  against  a  different  background. 
The  degree  of  dissimilarity  of  these  images,  together  with  the 
unlikeness  of  their  backgrounds,  is  another  sensory  cue  to  the 
perception  of  depth. 

Visual  space  perception  includes  responses  to  objects  seen 
above,  below,  to  the  right,  or  to  the  left.  The  difference  in 
stimulation  which  serves  to  distinguish  such  perceptions  from 
each  other  is  twofold.  The  part  of  the  retina  stimulated  is  dif- 
ferent and,  if  fixation  follows,  the  eye  movements  involved  in 
fixating  the  stimulating  object  are  different.  These  eye  move- 
ments afford  various  movement-produced  stimuli. 


118  PERCEPTION 

Visual  Perception  of  Objects 

Objects  give  not  only  such  stimuli  as  elicit  space  percep- 
tion, but  furnish  their  own  characteristic  pattern  and  color 
stimulation.  This  printed  page  contains  words  of  many  dif- 
ferent patterns  and  the  corresponding  image  patterns  on  the 
retina  serve  as  the  sensory  cues  for  many  different  percep- 
tions. As  the  page  is  moved  away  from  the  eye  the  images 
become  smaller,  but  we  call  the  patterns  the  same. 

It  is  probable  that  the  similarity  of  our  responses  to  an 
object  seen  at  different  distances  is  due  to  the  fact  that  an 
object  affords  a  continuous  stimulation  as  it  moves  toward  us 
or  away  from  us.  The  pattern  of  the  letter  H  is  seen  in  all 
sizes  as  the  letter  approaches  the  eye.  His  mother  seen  at  a 
distance  of  three  feet  looks  to  the  baby  like  his  mother  seen  at  a 
distance  of  ten  feet  because  he  has  continuously  fixated  her 
and  has  maintained  other  responses  toward  her  as  she  changes 
her  position.  If  it  were  not  for  this  gradual  change  of  size  of 
images  cast  by  approaching  and  receding  objects  it  is  probable 
that  all  visual  patterns  of  dissimilar  size  would  arouse  wholly 
different  perceptions.  Due,  however,  to  this  sequence  of  stim- 
ulation, and  to  the  overlapping  of  responses,  patterns  of  dif- 
ferent size  often  arouse  practically  the  same  perception. 

Because  of  another  sequence  of  stimulation,  patterns  of 
dissimilar  form  tend  to  arouse  similar  perceptions.  As  our 
friend  turns  his  head  he  casts  upon  our  retina  an  image  of 
gradually  changing  shape.  All  this  time  we  are  acting  toward 
him  in  the  same  way.  For  this  reason  the  full  face  and  the 
profile  photographs  of  our  friend  seem  much  more  alike  to  us 
than  the  full  face  and  the  profile  photographs  of  a  stranger. 
As  we  handle  a  cylindrical  tobacco  can,  the  image  of  its  top 
changes  from  a  circular  image  to  an  elliptical  image  whose 
smaller  axis  gradually  diminishes.  The  degree  of  resemblance 
of  two  patterns  certainly  depends  in  part  on  their  relative 
position  in  such  a  temporal  sequence  of  stimulation. 


PERCEPTION  119 

Retinal  stimulation  from  objects  differs  in  color,  and 
various  combinations  of  color  may  enter  into  the  retinal  pat- 
tern. Certain  colors  are  characteristic  of  particular  objects 
and  substances,  and  the  state  of  objects  is  often  indicated  by 
variations  in  color.  We  avoid  picking  up  the  poker  by  the  red 
end ;  we  cease  cooking  food  when  it  is  sufficiently  brown ;  and 
we  eat  a  red  apple  rather  than  a  green  one. 

Auditory  Space  Perception 

The  direction  of  an  object  is  roughly  perceived  by  means 
of  the  ears,  because  when  the  object  is  not  in  the  median  plane 
it  stimulates  one  ear  more  than  the  other.  The  direction  of  a 
sounding  object  which  is  in  this  median  plane,  in  front,  above, 
or  behind  us,  is  perceived  very  inaccurately.  The  evidence  of  a 
person  who  testifies  in  court  that  he  heard  a  revolver  shot 
just  ahead  of  him  on  a  dark  night  should  never  be  admitted, 
although  his  testimony  that  the  shot  came  from  the  right  may 
be  of  considerable  value. 

The  direction  of  a  continuous  sound  may  be  fairly  well 
located  by  turning  the  head  toward  the  side  at  first  more 
strongly  stimulated.  When  the  sound  is  heard  equally  by  the 
two  ears  the  face  is  directed  toward  the  source  of  the  sound. 
The  shape  of  the  external  ear  is  responsible  for  slight  differ- 
ences in  the  intensity  of  a  sound  as  it  comes  from  one  direc- 
tion or  another.  For  this  reason  we  may  have  a  meagre  per- 
ception of  an  object's  being  before  or  behind  even  when  we 
do  not  move  the  head. 

If  a  familiar  object  emits  a  sound  of  fairly  constant  in- 
tensity, this  intensity  is  a  cue  for  perceiving  how  far  away 
the  object  is.  Telephone  bells,  fog  horns,  bumble  bees,  alarm 
clocks,  automobiles,  and  even  footsteps,  human  voices,  rust- 
ling leaves,  and  falling  objects  arouse  distance  perceptions  ac- 
cording to  the  intensity  of  the  stimulation.  The  intensity  of 
a  wholly  unfamiliar  sound  would  be  no  cue  to  the  remoteness 
of  its  source. 


120  PERCEPTION 

The  echoes  which  are  reflected  from  objects  furnish  a 
sensory  aid  to  our  perception  of  distance.  These  echoes  are 
notably  of  assistance  to  the  blind,  who  find  it  easier  to  avoid 
obstacles  when  they  walk  with  heavy  shoes  on  resounding 
pavements  or  when  they  tap  the  ground  with  a  stick.  If  the 
reflecting  surface  is  several  feet  away,  not  only  the  intensity 
and  the  direction  of  the  echo,  but  the  time  interval  between  the 
original  noise  and  its  echo  may  assist  in  the  distance  percep- 
tion. 

Auditory  Perception  oe  Objects 

The  sounds  which  we  hear  about  us  are  combinations  of 
simple  tones,  each  tone  having  a  different  pitch.  A  tone  is 
made  up  of  simple  vibrations  of  a  single  rate.  Its  pitch  de- 
pends upon  the  rate  or  frequency  of  these  vibrations.  Rapid 
vibrations  are  high  pitched  and  slow  vibrations  are  low  pitch- 
ed. Any  complex  sound  may  be  analyzed  into  its  pure  tone 
components.  When  a  harp  string  is  plucked  the  resulting 
note  has  a  fundamental  tone,  caused  by  the  string's  vibrating 
as  a  whole,  and  a  great  many  tones  of  higher  pitch  (over- 
tones) which  are  caused  by  the  more  rapid  vibrations  of  parts 
of  the  string.  A  well  made  tuning  fork  has  practically  no 
overtones  so  that  the  sound  which  it  produces  approximates  a 
pure  tone. 

Any  note,  such  as  middle  C,  is  different  when  sounded 
on  a  piano,  a  violin,  a  banjo,  or  a  harp.  This  difference  is 
called  a  difference  of  timbre,  and  is  due  to  differences  in  the 
intensities  of  the  various  overtones  which  each  instrument 
produces.  Voices  of  men,  women,  and  children  differ  in  tim- 
bre and  this  is  also  true  of  the  voices  of  individuals. 

The  overtones  in  a  musical  sound  have  vibration  rates 
which  are  all  multiples  of  the  vibration  rate  of  the  funda- 
mental tone.  A  noise  is  made  up  of  a  combination  of  tones 
whose  vibration  rates  are  in  no  simple  ratio.  The  sounds  of 
a  passing  locomotive,  of  paper  being  crumpled,  and  of  a  slam- 


PERCEPTION  121 

ming  door,  are  complexes  of  tones  in  disorderly  confusion  and 
are  called  noises. 

The  diversity  of  noises  is  due  to  the  peculiar  structure 
of  the  objects  whose  vibration  causes  them,  and  so  each  kind 
of  object  has  its  characteristic  sound.  These  characteristic 
sounds  serve  as  the  cues  for  auditory  perception  of  objects. 
The  sounds  of  sawing,  hammering,  or  extracting  rusty  nails 
can  hardly  be  mistaken.  We  distinguish  the  passing  automo- 
bile from  the  passing  street  car.  The  jingling  of  coins  and  the 
jingling  of  a  bunch  of  keys  are  sufficiently  different  to  afford 
different  perceptions. 

Sounds  may  shift  from  one  fundamental  pitch,  from  one 
intensity,  or  from  one  timbre  to  another.  This  shifting,  as 
well  as  a  certain  duration  and  rhythm,  is  characteristic  of 
certain  objects  and  events.  Words,  and  vocalization  in  general, 
more  than  any  other  sounds,  depend  upon  this  change  of  tonal 
composition  and  this  modulation  of  intensity  for  their  effect- 
iveness as  sensory  cues. 

Olfactory  Perception 

Odor  stimuli  are  of  little  use  as  sensory  cues  for  percep- 
tion of  the  direction  of  the  odorous  object.  This  is  because  a 
change  of  orientation  changes  but  little  the  intensity  of  odor 
stimulation.  The  gases  which  emanate  from  an  object  and 
which  are  borne  on  the  wind  may  affect  our  sense  organs  long 
after  the  source  of  the  odor  has  been  removed.  Objects  may 
be  seen  and  heard  only  when  present,  and  changes  of  position 
modify  their  stimulation.  Because  of  this,  light  and  sound  are 
the  best  cues  for  direction  perception. 

Energetic  emotional  responses,  many  of  them  instinctive, 
are  given  to  odor  stimuli.  This  drive  results  in  trial  and  error 
behavior  until  a  more  definite  spatial  perception  of  the  object 
is  obtained  through  other  senses.  There  is  a  compensation 
for  the  absence  of  odor  space  perception  in  this  drive-aroused 
trial  and  error  behavior.    The  odor  of  food  starts  the  animal 


122  PERCEPTION 

on  its  search,  although  it  may  have  no  perception  of  where  the 
food  is.  As  it  nears  the  food  the  odor  becomes  more  intense 
and  the  animal's  explorations  more  thorough  at  this  spot. 

A  hound,  crossing  the  trail  of  a  fox,  probably  does  not 
perceive  by  the  use  of  his  nose  alone  the  direction  in  which  the 
fox  has  gone.  If  he  proceeds  in  the  wrong  direction  the  trail 
becomes  fainter,  whereupon  he  is  apt  to  turn  about  and  follow 
a  scent  which  becomes  increasingly  warmer.  As  he  approach- 
es the  fox  his  excitement  increases  and  this  keeps  him  from 
turning  back  once  he  is  rightly  headed.  The  ability  of  an  ant 
to  take  the  right  direction  when  placed  on  a  trail  is  probably 
due  to  its  familiarity  with  the  surface  over  which  it  has  fre- 
quently walked,  and  not  due  to  any  mysterious  odor  mechan- 
ism for  keeping  its  homeward  course. 

Different  odors  arouse  different  emotions  and  lower  the 
thresholds  of  particular  reactions.  This  is  often  the  result  of 
conditioning,  but  is  sometimes  instinctive.  Kittens,  before 
their  eyes  are  opened,  and  without  previous  experience  of 
puppies,  will  raise  the  head  and  "spit"  when  a  puppy  is  intro- 
duced into  their  cage.  The  odor  of  a  possible  mate  causes  gen- 
eral restlessness  among  most  lower  animals  and  lowers  the 
threshold  of  mating  responses.  The  odor  of  food  causes  hun- 
ger and  the  odor  of  spoiled  food  causes  nausea.  The  ant  stim- 
ulated by  a  strange  hive  odor  shows  fear,  and,  when  confront- 
ed with  one  of  its  own  group  which  has  been  artificially  per- 
fumed with  the  odor  of  a  strange  hive,  shows  fight.  The  odor 
of  a  crowd  probably  has  a  quieting  and  depressing  effect  upon 
human  beings. 

The  olfactory  lobes  in  the  human  brain,  as  compared  with 
those  in  the  brains  of  most  lower  animals,  are  relatively  small, 
and  man's  odor  perceptions  are  relatively  meagre.  Standing 
upon  his  hind  legs  man  has  a  wider  visual  horizon  and  less  op- 
portunity for  bringing  his  nose  in  contact  with  objects.  So 
with  his  increasing  dependence  upon  vision  there  seems  to 
have  been  a  falling  off  in  his  use  of  the  nose. 


PERCEPTION  123 

The  poverty  of  man's  odor  perceptions  is,  however,  not 
wholly  due  to  the  lack  of  an  adequate  mechanism.  With  care- 
ful practice  a  great  improvement  in  odor  perceptions  is  pos- 
sible. Blind  persons,  tea  and  wine  tasters,  and  connoisseurs  in 
food  often  show  an  interesting  superiority  in  odor  discrimina- 
tion. 

The  diversity  of  odor  stimuli,  their  capacity  for  arousing 
dissimilar  responses,  and  the  many  possible  combinations  of 
these  stimuli  enable  us  to  distinguish  objects  with  considerable 
accuracy  by  means  of  this  sense.  Not  only  individual  objects 
but  classes  of  objects  as  well  have  their  characteristic  odor. 
Things  which  are  not  seen  may  often  be  recognized  by  their 
scent  as  tobacco,  cheese,  frying  bacon,  coffee,  or  fresh  bread. 
All  marine  animals  smell  somewhat  alike.  So  do  most  flowers 
and  most  fruits. 

The  compromise  reactions,  which  grow  up  about  objects 
as  a  result  of  our  responding  to  the  various  stimuli  which  thev 
offer,  become  attached  to  the  odor  stimuli  which  the  objects 
furnish,  and  in  this  way  instinctive  responses  of  one  sort  are 
often  replaced  by  learned  responses  of  quite  another.  The 
odors  of  whiskey,  tobacco,  cheese,  and  clams  are  distasteful 
to  most  children,  but  are  popular  among  adults. 

KlNAESTHETlC  AND  STATIC  PERCEPTION 

The  perception  of  objects  from  muscle-sense  cues  has  al- 
ready been  considered.  Nearly  all  bodily  responses  are  de- 
termined in  part  by  muscle  and  static  sense  stimulation  which 
results  from  our  position  and  our  movement.  Without  move- 
ment-produced stimuli  to  the  proprioceptors  in  the  legs  we 
would  be  unable  to  walk.  Jar  and  displacement  of  muscles  and 
viscera  give  us  perceptions  of  being  jolted,  dropped,  or  car- 
ried about. 

Our  perception  of  rotary  direction  is  not  confined  to  in- 
stinctive responses  of  head  turning  and  eye  movements.  Stim- 
ulation of  the  semicircular  canals  brings  about  many  learned 


124  PERCEPTION 

responses  which  maintain  equilibrium  in  such  acts  as  dancing, 
boxing,  or  tennis  playing. 

Touch  Perception 

The  way  we  identify  the  part  of  the  body  which  is  touch- 
ed needs  no  elaborate  explanation.  A  perception  is  always  a 
response  and  the  stimulation  of  differently  located  sense  or- 
gans naturally  provokes  different  responses.  To  a  touch  on 
the  palm  of  his  left  hand  a  baby  responds  by  closing  that  hand. 
Pricked  on  the  right  toe  he  flexes  the  right  leg.  Superimposed 
upon  these  instinctive  movements  are  the  learned  responses 
given  to  objects  which  he  sees  in  contact  with  his  body,  and 
which  he  feels  in  the  process  of  manipulation. 

Time  Perception 

The  sequence  and  duration  of  events  in  the  external  world 
are  as  real  as  the  objects  which  the  world  contains.  The  com- 
mon sense  justification  for  this  view  is  the  fact  that  events 
keep  time  with  each  other.  Two  objects  which  are  dropped  to- 
gether from  the  same  height  strike  the  ground  together.  Every 
time  they  drop  the  same  number  of  seconds  is  ticked  off  on  the 
watch.  Bodily  functions  are  also  synchronized  with  external 
events  and  with  each  other.  Our  intestinal  tract  is  a  not  in- 
accurate time  piece,  and  we  know  the  lunch  hour  by  our  per- 
istalsis as  well  as  by  the  clock.  Thus  we  have  an  orderliness 
of  stimulation  which  determines  an  orderliness  of  perceptual 
responses. 

The  perception  of  duration  involves  some  such  response 
as  saying  to  ourselves,  "While  we  have  been  talking,  the  bank 
has  probably  closed  for  the  day,  the  postman  has  come  and 
gone,  and  the  train  on  which  our  friends  left  has  reached  the 
city."  We  are  assisted  in  this  perception  by  knowing  that  the 
bank  closes,  the  postman  comes,  and  the  train  reaches  its  des- 
tination all  at  the  same  time.  We  would  be  much  more  certain 
that  all  these  events  have  occurred  if  we  were  to  look  at  our 


PERCEPTION  125 

watch,  but  even  in  the  absence  of  a  watch  we  are  likely  to  be 
correct  in  our  perception. 

Men  have  learned  that  of  all  the  orderly  changes  in  the 
external  world,  the  series  of  changes  in  the  position  of  the 
stars  with  reference  to  fixed  points  in  an  observatory  is  the 
most  dependable.  This  simply  means  that  from  knowing  the 
hour  angle  of  a  star  we  can  infer  more  concerning  other  events 
than  from  knowing  the  stage  of  completion  of  any  other  order- 
ly sequence  found  in  nature.  Because  of  this  we  call  astro- 
nomical events  the  most  regularly  recurrent  and  accept  them 
as  a  convenient  standard  of  reference. 

Our  perception  of  time,  though  nearly  always  aided  by 
periodic  stimuli  from  orderly  events  in  our  environment,  may 
be  independent  of  these  stimuli.  It  is  by  no  means  impossible 
to  guess  successfully  the  amount  of  time  which  has  elapsed 
since  we  entered  the  room.  The  question  how  we  do  this  may 
be  partly  answered  by  recalling  the  facts  of  forgetting. 

When  an  act  has  been  performed  once  and  is  then  per- 
formed again,  the  ease  of  the  second  performance  depends  up- 
on the  amount  of  time  which  has  elapsed  since  the  first.  This 
ease  of  performance,  or  degree  of  positive  adaptation,  attaches 
to  reminiscences  as  well  as  to  overt  acts.  When  we  ask  our- 
selves how  long  we  have  been  sitting  here  we  rehearse  the 
events  which  occurred  when  we  entered  the  room.  This  re- 
hearsal involves  looking  at  the  door  through  which  we  entered, 
making  minimal  movements  which  correspond  to  such  acts  as 
entering,  saying  what  was  said  at  that  time,  or  taking  our 
seats.  The  amount  of  positive  adaptation  which  exists  in  these 
acts  of  rehearsal  after  any  lapse  of  time  is  a  cue  for  our  per- 
ception of  the  length  of  time  which  has  passed.  Cues  of  this 
sort  are  acknowledged  in  popular  speech  by  such  words  as 
"I  remember  it  as  though  it  were  yesterday"  or  "The  boat  has 
just  whistled." 

A  yet  more  effective  cue  to  our  perception  of  duration  is 
our  recalling  the  acts  or  events  which  have  filled  the  time  in 
question.     Recalling  events  is  not  possible  unless  there  were 


126  PERCEPTION 

perceptual  responses  when  the  events  took  place,  and  recall  is 
a  somewhat  incomplete  repetition  of  these  responses. 

All  events  which  fill  any  period  of  time  vary  more  or  less 
in  rate  of  occurrence  when  referred  to  the  astronomical  stand- 
ard, but  many  of  them  are  sufficiently  periodic  to  be  depend- 
able as  measures  of  time.  Pulse,  respiration,  and  the  rhythm 
of  walking,  talking,  or  eating  are  sufficiently  periodic  to  en- 
able us  to  perceive  time  as  long  or  short  according  as  it  con- 
tains more  or  fewer  of  these  events.  The  recollection  of  many 
diverse  events  may  also  enter  into  our  perception  of  time. 

The  increasing  fatigue  which  results  from  maintaining  a 
bodily  posture  is  significant  of  the  time  which  has  elapsed 
since  the  posture  was  taken  up.  So  also  is  the  increasing  stim- 
ulation from  holding  the  breath  during  short  intervals  of 
close  attention.  An  interval  seems  longer  when  the  muscles 
are  tense  and  the  respiration  and  pulse  are  rapid. 

Judgement 

Even  the  simplest  reflex  is  not  given  immediately  follow- 
ing stimulation.  There  is  a  period  of  latency  in  both  sense  or- 
gan and  muscle,  and  some  time  is  required  for  the  nervous  im- 
pulse to  traverse  the  reflex  arc.  Probably  the  shortest  reflex 
time  is  .02  second. 

If  we  are  asked  to  respond  to  the  sound  of  a  bell  by  lift- 
ing the  hand  as  quickly  as  possible,  the  interval  between  stim- 
ulus and  response  is  found  to  be  about  .15  second.  This  is 
perception  in  its  simplest  form. 

The  perception  of  the  more  complex  situation  which  in- 
volves speaking  the  name  of  a  familiar  object  exposed  to  view 
requires  about  .5  second.  More  elaborate  perceptual  responses 
to  complex  situations  require  a  still  longer  time. 

Perceptions  of  situations  which  contain  a  novel  combina- 
tion of  stimuli  have  a  comparatively  long  reaction  time,  and 
these  perceptions  we  call  judgments.  There  is  no  sharp  dis- 
tinction between  slow  perceptions  and  rapid  judgments.    The 


PERCEPTION  127 

slowness  which  characteries  judgment  may  be  due  to  any  one 
of  several  causes. 

The  simplest  cause  for  delay  is  the  weakness  or  meagre- 
ness  of  the  sensory  stimulation.  Music  heard  faintly  in  the 
distance  may  not  at  once  be  recognized  as  any  particular  melo- 
dy. Objects  seen  in  the  twilight  are  identified  with  difficulty. 
An  unfinished  drawing  may  require  a  moment  of  study  before 
we  decide  what  it  represents. 

In  the  presence  of  equivocal  stimuli  the  final  perception 
is  often  delayed  until  facilitating  habits  are  brought  into  play. 
We  may  waken  from  sleep  to  find  the  odor  of  smoke  in  the 
house.  No  elaborate  perception  may  result  until  it  dawns 
on  us  that  we  read  in  last  night's  paper  of  a  forest  fire  in  the 
neighborhood.  In  this  way  a  perception  may  be  completed  as 
a  result  of  the  slow  action  of  reenforcements  which  we  already 
possess,  and  without  further  explanation  of  the  objective  sit- 
uation. 

A  novel  combination  of  stimuli  brings  about  a  comprom- 
ise response,  and  this  response  is  slower  than  one  which  has 
been  practised.  When  we  meet  a  friend  who  has  removed  his 
moustache,  our  perception  is  both  slow  and  changed  in  char- 
acter. If  the  objects  surrounding  the  bee  hive  have  been  mov- 
ed about,  the  returning  bee  shows  excitement  and  takes  a  long- 
er time  to  enter  the  hive.  In  driving  an  unfamiliar  automobile 
our  responses  are  less  prompt  and  necessarily  modified.  These 
responses  are  changed  in  character  because  a  different  com- 
bination of  neural  mechanisms  has  been  called  into  play  by  a 
new  aggregation  of  stimuli.  The  lengthened  time  of  responses 
is  a  result  of  the  interference  between  the  mechanisms  in- 
volved. Probably  no  two  responses  are  wholly  compatible,  and 
in  extreme  cases  the  interference  may  result  in  mutual  inhi- 
bition. 

A  dog  that  is  first  trained  to  come  when  his  master  calls 
him  may  later  respond  to  the  call  of  a  stranger,  even  though 
the  stranger's  appearance,  tone  of  voice,  and  odor  may  differ 


128  PERCEPTION 

from  those  of  his  master.  The  dog's  response  depends  upon 
both  the  similarity  and  the  differences  between  the  new  and 
the  old.  A  baby  that  has  learned  to  say  "duck"  while  looking 
at  the  duck  in  his  picture  book  is  likely  to  disregard  differences 
and  to  call  any  bird  a  duck.  If  a  hat  is  sailed  over  the  chicken 
yard  the  chicks  may  run  to  cover,  giving  the  response  which 
is  customary  when  a  hawk  appears.  A  hunting  dog  may  be 
thrown  into  great  excitement  if  his  master  leaves  the  house 
carrying  a  broomstick  as  though  it  were  a  gun.  In  all  these 
cases  the  animals  have  responded  to  those  stimuli  in  the  new 
situations  which  are  identical  with  stimuli  occurring  in  the 
original  situations.  The  new  features  may  sometimes  greatly 
modify  the  response  and  may  sometimes  be  almost  wholly  dis- 
regarded. In  man,  and  to  some  extent  in  lower  animals,  these 
new  features  commonly  bring  into  play  reaction  tendencies 
which  either  inhibit  or  facilitate  an  habitual  response,  or 
which  result  in  a  compromise  response. 

Counterfeit  money  is  sufficiently  different  from  real 
money  to  furnish  a  cue  for  its  rejection.  A  stranger  may  look 
almost  like  an  acquaintance,  but  a  minor  dissimilarity  keeps  us 
from  speaking  to  him.  We  may  be  about  to  claim  a  trunk  in 
the  baggage  room  until  we  observe  some  strange  character- 
istic about  it  which  causes  us  to  search  further.  In  these  ways 
response  tendencies  are  prevented  by  our  taking  note  of  some 
detail  in  the  new  situation  which  was  absent  when  the  response 
was  learned. 

One  of  the  laboratory  guinea-pigs  had  in  its  cage  a  paste- 
board nest-box  with  an  entrance  on  the  side.  One  day  it  gnaw- 
ed a  small  hole  in  the  top  of  the  nest-  box  and  immediately  aft- 
erwards, on  being  given  a  piece  of  carrot,  sat  down  beside  this 
hole  to  eat.  The  food  accidentally  fell  through  the  hole  into 
the  nest-box  and  the  animal  made  a  vain  effort  to  crawl 
through  the  small  hole  to  recover  the  food.  Through  the  hole 
it  could  both  see  and  smell  the  food  and  the  bedding  in  the 
interior   of    the    box.      Without  repeating   the  effort  to  get 


PERCEPTION  129 

through  the  hole  it  scrambled  down  the  side,  ran  through  the 
entrance,  and  seized  the  food.  This  response,  though  facil- 
itated by  the  food,  was  of  course  given  to  the  familiar  bedding, 
but,  because  the  food  and  bedding  were  adjacent,  the  move- 
ment led  to  the  food.  If  the  bedding  had  not  been  present, 
the  food  would  not  have  been  recovered.  It  is  thus  evident 
that  attending  circumstances  are  often  the  most  important  fac- 
tors in  guiding  the  animal  to  a  consummatory  response. 

Judgments  are  influenced  by  temporary  reaction  tenden- 
cies persisting  from  recent  behavior.  Going  to  a  funeral  dis- 
torts our  sense  of  humor  for  some  time  afterward.  The  sen- 
tence which  a  magistrate  imposes  on  a  criminal  is  often  part- 
ly determined  by  circumstances  attending  the  previous  case. 
The  physician's  diagnosis  is  nearly  always  colored  by  what  he 
has  discovered  concerning  other  patients  recently  seen. 

We  often  have  a  tendency  to  action  in  the  absence  of  the 
object  whose  manipulation  constitutes  the  act.  While  dressing 
for  dinner  a  man  may  discover  that  he  is  without  a  collar 
button.  If  neither  shops  nor  friends  are  at  hand,  and  if  he  is 
a  person  of  intelligence,  he  looks  about  him  for  a  substitute 
article  with  which  to  fasten  his  collar.  None  of  the  objects 
which  his  eye  falls  upon  may  seem  suitable  to  him  until  final- 
ly he  discovers  a  paper  clip,  which  he  fashions  into  a  button. 
The  perception  of  an  object  as  something  which  will  serve 
our  purpose  is  a  form  of  judgment  which  may  attain  con- 
siderable subtilty.  The  perception  of  an  act  as  the  right  thing 
to  do  is  a  judgment  of  much  the  same  kind,  and  successful 
judgments  of  this  sort  characterize  the  highest  development  of 
behavior. 

A  judgment  may  involve  a  choice  of  alternative  re- 
sponses, as  when  a  player  makes  a  move  in  chess  or  plays  a 
certain  card  rather  than  another.  We  speak  of  a  situation  as 
offering  a  choice  only  when  two  or  more  response  tendencies 
are  approximately  equal.  When  the  conflicting  tendencies  are 
of  almost  equal  strength  the  delay  in  judgment  is  greatest. 

-5 


130  PERCEPTION 

Judgments  are  often  verbal.  The  word,  which  is  itself  a 
cue  to  response  tendencies,  is  elicited  by  the  situation  and 
serves  to  classify  the  things  we  experience. 

Reasoning  is  a  series  of  judgments,  each  consecutive 
judgment  resulting  from  the  stimulation  and  from  the  neural 
reorganization  which  the  preceding  judgment  produces.  As  a 
result  of  verbal  reasoning  incipient  action  tendencies  may  be 
aroused  and  consummated,  or  inhibited  and  drained  into  other 
response  mechanisms. 

Conviction  and  Beuef 

Conviction  and  belief  may  be  described  as  the  attachment 
of  response  tendencies  to  verbal  statements  which  are  either 
heard  or  spoken.  These  response  tendencies  may  themselves 
be  verbal  or  they  may  be  tendencies  to  other  forms  of  behavior, 
such  as  overt  acts  or  emotional  expression.  The  proposition, 
"Toadstools  are  poisonous,"  is  believed  when  we  refuse  to  eat 
them,  when  grave  apprehension  follows  our  having  eaten  them 
by  mistake,  when  we  try  to  prevent  our  friends  from  eating 
them,  and  when,  in  response  to  questioning,  we  declare  that  to 
eat  toadstools  will  result  in  illness.  When  any  of  these  re- 
sponses is  diminished  or  absent,  we  say  that  the  conviction  is 
not  complete.  Lower  animals  that  avoid  eating  toadstools 
are  not  said  to  do  so  as  a  result  of  a  conviction  or  a  belief, 
because  their  avoidance  is  not  conditioned  upon  a  verbal  state- 
ment. 

We  are  convinced  of  the  truth  of  the  proposition,  "Influ- 
enza is  contagious,"  if  the  tendency  to  say  these  words  follows 
our  discovery  of  a  supposed  influenza  case  and  if  this  verbal 
response  makes  us  cautious. 

The  moral  conviction  that  it  is  wrong  to  play  tennis  on 
Sunday  consists  first  of  all  in  saying  so  when  tennis  is  suggest- 
ed. Further  than  this,  our  belief  consists  in  a  tendency  not 
to  play,  and  in  displaying  resentment  toward  those  who  do 
such  a  thing.    The  belief  that  debts  should  be  paid  involves  ad- 


PERCEPTION  131 

vocating  this  statement,  having  a  consequent  tendency  to  pay 
debts,  and  a  show  of  remorse  when  this  tendency  is  prevented. 
When  a  hypocrite  merely  advocates  this  form  of  honesty  and 
does  not  pay  his  debts  and  does  not  regret  his  failure  to  do  so, 
we  recognize  the  incompleteness  of  his  belief. 

A  belief  may  be  said  to  be  systematized  when  to  alter  it 
would  involve  a  modification  of  many  other  beliefs,  opinions, 
and  habits.  It  is  difficult  for  the  West  Indian  Negro  to  give 
up  his  belief  in  ghosts  because  many  of  his  convictions  involve 
the  word.  His  dead  friends  have  become  ghosts;  many  other- 
wise inexplicable  events  are  caused  by  ghosts ;  the  graveyard 
is  awful  because  of  the  presence  of  ghosts ;  and  the  exact  ap- 
pearance and  habits  of  ghosts  have  been  described  to  him  in 
voodoo  teaching.  The  college  student  may  be  slightly  super- 
stitious concerning  ghosts,  but  because  any  such  belief  is  un- 
sytematized,  it  is  easily  dissipated. 

When  a  belief  that  is  unshared  by  the  believer's  asso- 
ciates stubbornly  resists  persuasive  argument,  and  when  it  is 
not  the  ordinary  result  of  such  experiences  as  the  believer  has 
had,  we  call  the  belief  a  delusion.  Delusions,  like  other  opin- 
ions, may  be  systematized  and  emotionally  reenforced,  in 
which  case  they  show  an  obstinate  persistency. 


CHAPTER  6 

HUMAN  MOTIVES 
The  Delayed  Reaction 

The  acts  we  perform  today  often  seem  to  be  the  direct 
result  of  the  stimuli  we  received  yesterday.  We  continually 
make  plans  for  tomorrow  and  when  the  time  comes  we  often 
carry  out  the  previous  day's  intention.  Is  this  lapse  of  time 
between  the  stimulus  and  the  reaction  a  true  latent  period  of 
response,  or  is  the  reaction  when  finally  given  simply  a 
response  to  memoranda  which  our  environment  affords?  If 
all  our  sense  organs  were  made  anaesthetic,  could  we  bear  in 
mind  the  fact  that  in  a  little  while  we  must  meet  an  engage- 
ment or  phone  to  a  friend?  Would  any  serious  thinking  be 
possible  to  a  person  totally  deprived  of  sensory  stimuli  and  in 
some  way  miraculously  kept  alive  ?  Unless  we  find  in  the  lab- 
oratory the  answer  to  such  questions  as  these  we  are  in  danger 
of  accepting  some  fanciful  hypotheses  as  to  the  way  thinking 
proceeds. 

The  central  nervous  system  while  isolated  might  con- 
ceivably be  capable  of  carrying  on  a  self  contained  interplay 
of  processes  which  would  ultimately  result  in  an  act,  but  the 
fact  remains  that  the  central  nervous  system  never  is  isolated 
from  the  effect  of  constant  sensory  stimulation.  Even  in  sleep 
and  in  surgical  anaesthesia  the  isolation  from  receptors  is 
only  partial. 

Hunter  constructed  a  choice-reaction  box  which  had  three 
passageways  leading  to  food.1  Any  two  of  these  passage- 
ways could  be  blocked  and  the  third  left  open.  The  open  pas- 
sageway, varied  at  random,  was  always  illuminated.  By  trial 
and  error,  the  animals  in  this  box  learned  to  select  the  illu- 
minated opening  and   to   avoid  the   others.     An  animal   so 

1  Hunter,   The  Delayed  Reaction  in  Animals  and  Children,  Animal  Behav.  Monogr.,  1913,  No.  1. 

(132) 


HUMAN  MOTIVES  133 

trained  was  then  placed  in  a  release  compartment  which  of- 
fered a  view  of  all  three  passageways,  but  from  which  it  could 
not  escape  until  freed  by  the  experimenter.  The  light  was 
turned  on  in  the  open  passageway  until  it  was  observed  by  the 
animal.  Then,  after  the  light  had  been  turned  off,  an  interval 
was  allowed  to  elapse  before  the  release  compartment  was 
opened.  Even  after  this  delay  the  animal  could  still  choose  the 
correct  exit.  Such  behavior  is  generally  referred  to  as  a  de- 
layed reaction.  Hunter  found  that  the  interval  between  the 
light  stimulus  and  the  response  could  be  as  long  as  from  1  to 
5  seconds  for  rats,  from  1  to  3  minutes  for  dogs,  and  more  than 
20  minutes  for  a  five-year-old  child. 

Rats,  cats,  and  dogs,  in  order  to  respond  successfully, 
had  to  maintain  their  orientation  throughout  the  interval. 
This  orientation  preserves  the  stimulating  effect  of  the  proper 
exit  until  the  animal  is  released.  The  sight  of  the  closed  bar- 
rier of  the  release  box  inhibits  the  movements  of  escape.  The 
opening  of  this  barrier  removes  this  inhibition,  and  furnishes 
a  facilitating  stimulus  to  the  escape  movements  which  the  sight 
of  the  fixated  passageway  has  throughout  tended  to  initiate. 
The  animal  that  maintains  its  orientation  throughout  the  in- 
terval presents  a  picture  of  balanced  reaction  tendencies,  each 
of  which  is  excited  by  a  persistent  stimulus.  When  one  of 
these  stimuli,  namely  the  release  barrier,  ceases  to  act,  the 
other,  the  fixated  passageway,  causes  a  response.  The  situa- 
tion which  is  here  at  work  is  easily  analyzed. 

Children,  even  though  they  had  lost  their  orientation  dur- 
ing the  interval,  were  able  to  respond  successfully.  Adults  do 
this  with  considerable  uniformity.  If  the  subject  is  carefully 
observed,  this  delay  in  reaction  no  longer  seems  to  be  a  true 
latency  of  response. 

The  response  tendency  toward  the  door  last  illuminated 
would  hardly  have  the  lowest  threshold  just  because  of  recen- 
cy of  excitation,  as  the  other  doorways  may  be  the  ones  last 
looked  at.    When  an  adult  subject  in  this  experiment  carefully 


134  HUMAN  MOTIVES 

observes  his  own  behavior,  one  of  the  following  factors  always 
seems  to  be  present  to  determine  his  correct  choice.  Some- 
times he  assumes  an  inconspicuous  orientation,  of  parts  other 
than  head  or  eyes,  when  he  sees  the  light,  and  maintains  this 
posture  until  the  interval  has  elapsed.  This  serves  as  his  cue 
when  he  is  released.  He  may  guard  against  doing  this,  how- 
ever, with  some  success.  More  frequently,  his  seeing  the  light 
in  a  particular  doorway  is  followed  by  some  characteristic 
movement  reserved  for  that  situation,  consisting  of  a  slight 
swaying  of  the  body  or  head,  slight  contraction  of  muscles  on 
one  side  or  the  other,  or  subvocal  speech  movements  corre- 
sponding to  words  which  designate  the  proper  doorway. 
These  minimal  movements  are  often  wholly  unobserved  by  the 
experimenter.  When  the  subject  is  released,  a  scrutiny  of  the 
doorways  will  revive  one  of  these  cue  movements,  which  seems 
to  depend  upon  recency,  and  upon  the  emotional  reenforcement 
characteristic  of  all  preparatory  responses  for  its  low  thresh- 
old. This  serves  in  turn  to  reenforce  the  proper  orientation 
and  approach  responses.  The  subject  usually  reports  that  his 
choice  does  not  depend  on  having  made  merely  the  original 
orientation  movements,  and  when  his  choice  is  correct  he  prac- 
tically never  fails  to  report  the  occurrence  of  some  additional 
cue  movement,  sometimes  a  series  of  such  movements,  which 
were  begun  while  the  orientation  was  still  maintained. 

If  a  stimulus  does  not  cause  an  immediate  response  of 
one  sort  or  another,  it  will  probably  never  cause  a  delayed 
response  of  any  kind.  If  a  mechanism  is  stimulated  and  the 
response  inhibited,  the  delayed  occurence  of  the  response,  in 
the  absence  of  the  original  stimulus,  is  due  either  to  a  main- 
tenance of  orientation  or  to  the  recurrence  of  some  condi- 
tioning stimulus,  usually  movement-produced. 

Suppose  that  a  man  is  called  to  dinner  while  in  the  midst 
of  work,  and  delays  his  response  until  he  has  reached  a  con- 
venient place  for  stopping.  Unless  he  changes  his  posture 
in  readiness  for  rising  or  maintains  an  uneasy  tension,  unless 


HUMAN  MOTIVES  135 

peristalsis  jogs  his  memory,  or  unless  sounds  from  the  dining 
room  remind  him  that  dinner  is  in  progress,  his  reaction  is 
very  likely  to  remain  delayed  until  he  is  called  again.  If,  when 
dinner  was  first  announced,  he  happened  to  be  looking 
at  the  paperweight  on  his  desk  as  he  promised  to  be  down  in  a 
moment,  a  casual  glance  at  the  paperweight  might  later  bring 
him  to  his  feet.  Some  sensory  cue  seems  essential  to  call  out  a 
delayed  response  once  the  original  stimulus  has  ceased  to  act. 
Such  a  sensory  cue  may  be  either  an  organic  stimulus  or  one 
external  to  the  body,  which,  having  occurred  along  with  the 
original  situation,  has  become  a  substituted  stimulus  for  the 
delayed  response.  Our  environment,  our  daily  routine,  and 
our  rhythmical  bodily  functions  are  full  of  memoranda  for 
these  postponed  reactions.  Lacking  these  helps  we  would  al- 
most never  carry  out  an  intention.  Having  made  an  engage- 
ment for  Monday  morning  we  keep  it  because  the  events  of 
Monday,  when  they  occur,  are  different  from  the  events  of 
Sunday.  No  response  is  ever  given  to  an  abstract  forty-eight 
hours  hence.  A  delayed  reaction  is  not  essentially  different 
from  any  other  conditioned  response. 

Preparatory  and  Consummatory  Responses 

When  we  attempt  to  describe  what  an  animal  is  doing, 
we  find  that  we  can  distinguish  between  certain  responses 
which  mark  the  end  of  a  series  of  acts  and  those  which  lead  up 
to  this  final  response.  We  may  see  a  dog  running  about  in  a 
field,  occasionally  picking  up  a  scent  and  following  it,  losing 
the  scent,  ranging  about  until  it  is  recovered,  and  barking, 
all  with  evident  excitement.  We  explain  his  behavior  by  say- 
ing that  he  is  after  a  rabbit,  although  it  is  evident  that  the 
rabbit  itself  is  not  acting  as  a  stimulus.  One  of  the  important 
stimuli  for  the  dog's  activity  is  the  scent  which  the  rabbit 
leaves  behind  it.  The  odor  prompts  the  dog  to  follow  the  trail 
with  his  nose  to  the  ground,  and  arouses  energetic  emotional 
responses.    A  part  of  the  movements  which  would  be  involved 


136  HUMAN  MOTIVES 

in  seizing  the  rabbit  are  also  present,  but  the  act  of  seizing 
cannot  be  entirely  carried  out  because  there  is  no  rabbit  near 
enough  to  be  seized.  That  the  stimuli  which  cause  the  dog 
to  hunt  are  in  part  internal  stimuli,  is  shown  by  the  fact  that 
this  behavior  appears  whenever  the  dog  has  been  for  a  time 
without  food. 

The  response  which  puts  an  end  to  this  activity  is  killing 
and  devouring  the  rabbit.  The  reason  that  the  activity  ends 
is  that  the  internal  stimuli  which  prompted  the  animal  to  range 
about  have  been  removed  by  the  act  of  eating. 

The  final  response  which  removes  these  stimuli,  by  alter- 
ing either  the  external  situation  or  the  internal  state  of  the 
animal,  is  called  a  consummatory  response.  The  series  of  re- 
sponses leading  up  to  this  final  response  are  called  preparatory 
responses. 

Preparatory  responses  are  governed  for  the  most  part  by 
the  external  situation.  When  a  dog  is  hungry  the  details  of 
his  behavior  are  determined  by  his  responses,  instinctive  or 
learned,  to  the  circumstances  in  which  he  finds  himself.  The 
odor  of  rabbit  causes  ranging  about,  and  in  the  case  of  a  dog 
that  has  once  caught  a  rabbit,  the  odor,  by  conditioning, 
arouses  eating  movements  in  so  far  as  they  may  be  given  in  the 
absence  of  food. 

These  eating  movements,  a  part  of  the  consummatory  re- 
sponse, are  interestingly  shown  by  a  dog  or  a  horse  when  in- 
accessible food  is  displayed.  Probably  a  part  of  the  consum- 
matory response  is  always  given  throughout  the  period  of 
preparatory  acts,  and  this  maintains  a  low  threshold  for  the 
consummatory  response  until  the  opportunity  for  giving  it 
in  its  entirety  arrives.  The  organs  of  response  involved  in  a 
consummatory  reaction  are  thus  in  a  state  suitable  for  use,  and 
the  stimuli  produced  by  this  making  ready  for  action  serve, 
after  repeated  experience,  to  condition  and  to  facilitate  the 
preparatory  responses.  This  state  of  readiness  in  effectors 
may  be  observed  throughout  the  interval  between  arousal  and 


HUMAN  MOTIVES  137 

consummation  in  such  acts  as  mating,  hunting,  nest-building, 
quarreling,  or  searching  for  a  lost  article.  It  is  this  which 
makes  the  dog  range  about  when  he  has  lost  the  scent,  with  the 
result  that  the  scent  is  again  picked  up. 

When  the  trail  is  lost  the  dog  is  left  with  an  aborted  ten- 
dency to  respond  to  an  odor  stimulus.  This  results  in  an 
emotional  reaction  which  reenforces  the  trial  and  error  be- 
havior by  which  the  scent  is  again  picked  up. 

The  Wish 

A  wish  is  an  emotionally  facilitated  tendency  toward  a 
consummatory  response  whose  consummation  is  delayed. 
This  delay  may  be  caused  by  the  inhibiting  action  of  an  an- 
tagonistic mechanism  when  the  situation  for  carrying  out  the 
reaction  is  present.  Or  it  may  be  caused  by  the  absence  of  the 
situation  necessary  for  carrying  out  the  act  when  the  tendency 
is  aroused  by  conditioning  stimuli.  Pending  the  consumma- 
tion of  an  act,  the  opportunity  for  which  is  present  and  inter- 
ference with  which  is  absent,  the  wish  may  be  slightly  in  evi- 
dence while  the  act  is  being  carried  out.  Thus  we  may  wish  to 
take  a  drink  of  water  while  preparing  to  do  so,  but  this  is  only 
because  the  act  of  securing  the  water  postpones  the  consumma- 
tory response.  The  other  occasions  on  which  wishing  for 
water  is  evident  are,  first,  when  water  is  present  and  we  are 
inhibited  from  drinking  by  some  such  circumstance  as  the 
presence  of  a  thirsty  friend,  and,  second,  when  a  dryness  of  the 
throat,  mention  of  water,  or  the  sight  of  an  empty  glass 
prompts  us  to  drink  and  no  water  is  to  be  had.  During  the 
delay,  in  either  case,  there  is  readily  apparent  the  growing 
emotional  reenforcement  which  is  characteristic  of  the  post- 
ponement of  any  consummatory  reaction.  All  wishes  are  con- 
summatory response  tendencies  whose  complete  expression  is 
interfered  with,  and  whose  postponement  arouses  emotional 
reenforcement. 


138  HUMAN  MOTIVES 

Attention 

Attention  is  the  orientation  of  sense  organs  toward  a 
source  of  stimulation  and  the  lowering  of  a  response  threshold. 
It  always  involves  more  or  less  preparatory  innervation  of  the 
effector  muscles.  Usually  associated  with  it  is  the  cessation 
of  most  movements  which  do  not  serve  to  explore  the  object 
which  is  attended  to.  Attention  is  most  evident  when  there  is 
a  balancing  of  reaction  tendencies,  in  which  case  the  orienta- 
tion is  more  persistent  because  the  muscle  contractions  by 
which  the  orientation  is  maintained  are  emotionally  re- 
enforced.  After  a  few  seconds  duration  the  muscular  ad- 
justment of  the  sense  organ  is  partly  lost,  but  due  to  move- 
ment-produced stimuli  which  this  loss  occasions  the  proper  ad- 
justment may  be  regained.  The  same  is  true  of  the  large 
muscle  groups  involved  in  the  orientation.  In  addition  to  the 
fluctuation  of  muscular  adjustment,  there  is  a  fluctuation  of 
conductivity  of  the  neural  arc,  probably  due  to  variation  in 
conductivity  of  the  synapse  and  to  the  irregular  drainage  and 
reenforcement  of  the  system.  Thus  we  always  have  a  sort  of 
fluttering  or  pulsation  in  attention,  even  though  careless  ob- 
servation may  seem  to  indicate  continuous  attention  lasting- 
several  minutes. 

The  movements  of  orientation  may  shift  from  object  to 
object  following  systematic  changes  in  a  situation.  Where 
this  shifting  is  present  there  is  likely  to  be  less  fatigue  and  more 
emotional  reenforcement  of  the  movements  on  which  the  orien- 
tation depends.  Attention  to  one  object  or  to  one  orderly  se- 
quence of  events  inhibits  responses  to  unrelated  stimuli,  both 
because  of  the  low  thresholds  established  by  the  intense  stim- 
uli which  result  from  the  orientation  and  because  of  the  facili- 
tation derived  from  many  component  responses  which  make 
up  habitual  acts. 

Voution 

A  voluntary  act  is  the  outcome  of  a  delayed  reaction  when 
reenforcement  reduces  a  high  threshold  of  response  or  brings 


HUMAN  MOTIVES  139 

to  an  end  the  balancing  of  incompatible  reaction  tendencies. 
This  reenforcement  is  furnished  by  movement-produced  stim- 
uli and  by  external  changes  in  the  environment.  It  is  possible 
that  the  balance  of  tendencies  might  be  lost  and  action  result 
without  external  coercion,  provided  one  of  the  two  opposed  re- 
action tendencies  fatigues  sooner  than  the  other.  Introspection, 
however,  usually  detects  either  a  bodily  change  or  a  change  of 
external  stimulation  as  an  antecedent  of  voluntary  movement. 

We  often  overlook  the  external  changes  which  affect  our 
choice.  We  may  be  undecided  whether  or  not  to  take  the 
morning  train  for  a  week-end  vacation.  With  opposed  ten- 
dencies to  action  mutually  inhibited,  we  delay  our  decision  to 
act,  but  as  the  time  grows  short  the  balance  is  disturbed,  so 
we  pack  our  bag  and  start.  Here  it  is  the  change  in  the  clock 
which  has  destroyed  the  equilibrium  of  our  hesitation,  al- 
though we  are  likely  to  credit  ourselves  with  having  made  an 
unaided  choice.  This  disturbance  of  balance  by  an  external 
event  needs  no  lengthy  discussion.  A  more  interesting  ante- 
cedent of  voluntary  movement  is  the  balance  destroying  stim- 
uli which  our  own  bodies  provide. 

The  opposed  reaction  tendencies  which  are  present  in  de- 
layed choice  never  leave  us  wholly  unmoved.  They  always 
bring  about  internal  responses  of  one  sort  or  another.  The 
energy  which  this  opposition  engenders  is  drained  into  other 
systems,  and  produces  either  slight  skeletal  movement  or  var- 
ious internal  changes.  Such  responses  provide  stimuli  which 
are  likely  to  reenforce  one  or  the  other  of  the  balanced  ten- 
dencies. If  enough  reenforcement  is  finally  piled  up  on  one 
side  to  destroy  the  balance,  a  voluntary  act  results. 

Some  of  these  internal  changes  are  difficult  to  observe  ex- 
cept introspectively,  and  such  a  method  never  gives  wholly  ac- 
curate information.  The  respiratory  changes  antecedent  to 
voluntary  movement  may  be  graphically  recorded,  and  serve 
as  a  good  illustration  of  balance  destroying  stimuli.  Such  a 
record  is  shown  in  Figure  29.  The  conditions  of  the  experiment 


140 


HUMAN  MOTIVES 


under  which  this  and     similar  records  were  secured  are  as 
follows : 

The  pneumograph  was  adjusted  at  the  axilla  level.  The 
subjects  selected  were  always  untrained  and  did  not  suspect 
the  purpose  of  the  experiment.  Most  of  them  did  not  know 
that  their  respiration  was  being  recorded.  Each  of  them  was 
seated  before  a  table  on  which  were  placed  three  small  strips  of 
cardboard.  The  following  instructions  were  then  given: 
"Wait  until  you  feel  that  you  wish  to  do  so,  then  place  these 
strips  of  cardboard  so  that  they  form  some  geometrical  fig- 
ure." The  time  of  the  first  observable  movement  of  the  sub- 
ject's hand  as  he  reached  for  the  strips  was  indicated  by  the 

BEGtIN    END 


Figure  29 — Respiratory  antecedents  of  voluntary  movement.  The  procedure  is 
described  in  the  text.  Voluntary  hand  movements  occurred  at  the  points 
marked  A  on  the  time  line.  Time  is  indicated  in  5  second  intervals.  The 
figure  is  traced  from  the  kymograph  record.  Apnoea,  following  deep  expira- 
tion, precedes  the  voluntary  movements. 


HUMAN  MOTIVES  141 

experimenter's  closing  a  switch.  A  characteristic  respiratory 
change,  similar  to  that  shown  in  figure  7,  was  observed  in  all 
but  one  of  the  twelve  subjects  employed.  These  movements 
consisted  of  a  deep  expiration,  the  hand  movement  being  made 
just  as  inspiration  was  begun.  The  inspiration  was  interrupted 
by  one  or  more  periods  of  apnoea,  while  the  initial  hand  move- 
ment was  being  executed.  If  the  reader,  preferably  with  eyes 
closed,  will  repeat  for  himself  these  respiratory  movements, 
exhaling  deeply  and  interrupting  his  inspiration  by  several 
periods  of  holding  the  breath,  he  will  be  conscious  of  a  gen- 
eralized innervation  especially  affecting  the  muscles  which  ex- 
tend the  arms.  It  is  easy  to  see  how  this  stimulation  from 
apnoea  may  so  reenforce  the  reaching  out  tendency  as  to  re- 
duce sufficiently  the  threshold  and  bring  about  the  act. 

Drive 

Having  considered  what  kind  of  response  is  naturally  given 
to  each  kind  of  stimulus,  how  new  stimuli  are  substituted  for 
old,  how  responses  are  integrated  into  new  combinations,  and 
how  delayed  responses  are  finally  brought  about,  there  remains 
the  question  why  some  acts  are  more  persistent  and  more  ener- 
getic than  others,  why  some  tendencies  are  imperious  and  some 
are  easily  discouraged.  It  is  not  sufficient  to  say  that  a  man's 
tendency  to  act  in  a  particular  way  is  strong  because  he  "wills" 
so  to  act.  Energetic  action  must  be  a  result  of  a  physiological 
mechanism  capable  of  releasing  and  conducting  the  necessary 
amount  of  nervous  impulse. 

We  cannot  escape  the  hypothesis  that  each  stimulus- 
response  mechanism  has  its  store  of  nervous  energy,  and  that 
nervous  impulses  are  drained  from  one  mechanism  to  another. 
In  this  way  energy  may  be  borrowed  and  a  mechanism  which 
so  borrows  it  is  said  to  be  reenforced.  Probably  every  stimu- 
lus-response mechanism  is  capable  of  action  without  reen- 
forcement,  but  few  mechanisms  ever  act  in  isolation. 


142  HUMAN  MOTIVES 

The  mechanisms  resulting  in  acts  of  love,  fear,  rage, 
hunger  ,  pain,  shame,  and  other  emotional  expressions  are 
supplied  with  a  great  amount  of  latent  energy.  From  these 
reservoirs  many  less  energized  mechanisms  receive  their  addi- 
tional drive. 

Any  act  becomes  emotionally  reenforced  once  it  has  been 
elicited  along  with  an  emotional  response,  the  emotion  becom- 
ing a  conditioned  response  either  to  the  stimulus  which  causes 
the  simple  act  or  to  the  movement-produced  stimuli  in  which 
the  act  results. 

Upon  the  conflict  of  certain  reaction  tendencies  there  re- 
sults such  emotions  as  grief,  anxiety,  shame,  and  remorse. 
The  effect  of  these  emotions  is  to  depress  or  inhibit,  rather 
than  to  facilitate  behavior  in  general.  These  emotions  usually 
arise  when  some  event  has  occurred  which  makes  it  difficult  or 
impossible  for  us  to  carry  out  an  habitual  consummatory  re- 
sponse. When  the  death  of  a  baby  removes  him  from  his 
mother's  arms,  the  tendency  to  fondle  him  is  still  present,  but 
can  not  be  expressed.  If  a  child  breaks  her  doll,  she  is  left 
with  a  futile  tendency  to  play  with  it.  A  man  who  is  put  in 
jail  is  inevitably  prevented  from  engaging  in  most  of  the  con- 
summatory responses  of  daily  life.  In  all  these  cases  grief  and 
the  depression  of  activity  result.  If  the  obstacles  to  action  in 
these  cases  had  not  been  insurmountable,  rage,  and  not  grief, 
would  have  been  aroused  and  activity  increased.  The  utility 
of  discouragement  and  melancholy  consists  in  that  the  victim 
of  circumstances  does  not  spend  himself  in  vain  effort. 

The  internal  changes  involved  in  emotional  responses 
affect  wide  areas  and  bring  about  sustained  stimulation  to 
many  proprioceptors.  The  diffuse  nature  of  emotional  stimu- 
lation is  easily  observed  in  any  one  suffering  from  a  toothache 
or  in  a  person  who  is  enraged  or  frightened. 

No  form  of  conduct,  excepting  routine  habit,  is  persist- 
ently engaged  in  unless  emotionally  reenforced.    Routine  habit 


HUMAN  MOTIVES  143 

itself  is  originally  established  with  the  aid  of  a  borrowed  emo- 
tional drive.  Dancing,  game  playing,  dangerous  sports,  gos- 
sip, theatre-going,  controversy,  and  business  speculation  are 
energetically  pursued  because  of  the  emotional  drive  which 
the  situations  arouse.  The  approbation  or  disapprobation  of 
our  fellows  furnishes  to  otherwise  weak  reaction  tendencies  an 
emotional  facilitation  without  which  we  would  never  finish 
the  day's  work. 

Due  to  social  convention  the  consummatory  responses  in 
such  acts  as  love,  rage,  and  fear  are  often  inhibited  or  blocked. 
During  a  conference  with  a  business  enemy  the  preparatory 
responses  of  rage  are  aroused,  but  the  general  situation  in- 
hibits killing.  With  the  blocking  of  this  consummatory  re- 
action an  ever  increasing  amount  of  dammed  up  energy  is  pro- 
vided, which  finds  outlet  not  in  physical  violence  but  rather  in 
attending  to  business  with  renewed  drive.  If  the  competitor 
wins  out  in  the  business  deal,  however,  this  energy  finds  outlet 
in  curses,  imprecations,  slander,  or  frequently  in  the  fabrica- 
tion of  a  story  which,  when  told  to  friends,  serves  to  justify 
failure  and  to  elicit  sympathy.  After  an  unpleasant  ordeal 
with  a  business  superior  a  man  is  likely  to  talk  to  himself  on 
the  way  home,  or  possibly  later  in  the  evening  to  find  some  ex- 
cuse for  disciplining  the  children. 

The  fascination  of  literary  fiction  is  produced  by  the 
author's  postponing  any  description  of  his  hero's  consumma- 
tory responses,  and  by  elaborating  his  preparatory  responses. 
Thus  the  reader's  interest  is  aroused  and  maintained.  Al- 
ways the  dawn  breaks  and  Scheherazade  ceases  saying  her 
permitted  say  just  as  the  hero  is  about  to  be  discovered  in  his 
hiding  place  ,  or  while  he  is  still  in  full  flight.  When  true  love 
begins  to  run  smoothly  the  story  is  ended. 

Emotional  reenforcement  is  largely  responsible  for  the 
tenacity  of  certain  memories  of  early  childhood.  The  situa- 
tions thus  remembered  are  nearly  always  exciting.  Out  of 
seven  hundred  "first  memories"  recently  collected,  more  than 


144  HUMAN  MOTIVES 

97  percent  were  the  results  of  highly  charged  emotional  ex- 
periences. The  event  which  leaves  us  unmoved  is  soon  forgot- 
ten, and  it  is  well  that  this  is  so,  for  an  event's  importance  is 
usually  proportional  to  its  emotional  effect. 

Sublimation 

In  the  laboratory,  when  men  and  girls  are  working  to- 
gether, much  diffuse  and  purposeless  movement  may  be  ob- 
served, which  would  not  occur  in  other  than  a  coeducational 
university.  Properly  utilized,  this  additional  drive  may  result 
in  effective  work.  The  utilization  of  dammed  up  drive  for 
acts  other  than  the  consummatory  reaction  to  which  it  would 
lead  if  uninhibited  is  called  sublimation. 

When  a  person  becomes  apathetic  toward  his  work  he  is 
frequently  not  fatigued.  When  this  is  so,  what  he  needs  is 
recreation,  not  rest.  He  may  go  to  the  theatre,  visit  a  friend, 
or  play  a  game  of  cards,  and  then  return  to  his  work  with  new 
enthusiasm.  This  drive  is  not  so  much  the  result  of  rest  as  it 
is  the  outcome  of  recent  preparatory  emotional  responses  in 
one  form  or  another.  Thus  we  distinguish  being  tired  from 
being  stale. 

In  the  case  of  children,  when  rage,  love,  or  fear  behavior 
is  initiated  but  blocked,  the  outlet  for  the  resulting  drive  is 
often  in  tears  or  laughter.  Giggling  is  characteristic  of  older 
children  under  similar  conditions,  and  may  be  shown  in  church, 
in  school,  or  anywhere  in  the  presence  of  the  opposite  sex. 
The  theatre  audience  laughs  most  heartily  at  indelicate  allu- 
sions. Laughter  may  occur  upon  the  sudden  passing  of  dan- 
ger or  upon  the  averting  of  a  quarrel.  Any  incongruity  in  a 
situation  may  cause  a  blocking  of  emotional  response  and  this 
is  probably  why  the  incongruous  is  often  whimsical. 

The  sublimated  drive  which  enables  men  to  surmount  ob- 
stacles is  of  various  kinds.  The  competitor  shows  a  dogged- 
ness  of  conduct  which  is  not  found  in  the  man  who  has  no 
rivals.    Love  makes  the  world  go  round.    "The  fear  o'  hell's  a 


HUMAN  MOTIVES  145 

hangman's  whip  to  haud  the  wretch  in  order."  Many  emo- 
tional states  are  derived  from  the  basic  elements  of  rage,  love, 
and  fear.  It  is  seldom  that  one  of  these  elements  is  lacking 
when  any  ambition  is  pursued  with  great  tenacity  of  purpose. 

It  is  necessary  to  recognize  certain  coenotropic  tendencies 
which  may  be  observed  in  all  young  children.  Children  seek 
opportunities  to  inflict  pain  on  others,  and  this  inclination  is 
called  sadism.  They  also  tend  in  certain  situations  to  seek 
painful  stimuli.  This  is  known  as  masochism.  They  show  a 
propensity  to  exhibit  their  bodies  and,  especially  from  conceal- 
ment, to  observe  the  bodies  of  others.  All  these  tendencies  are 
undoubtedly  a  part  of  sex  behavior.  A  derivative  form  of  the 
tendency  to  cause  pain  to  others  is  seen  in  bossing  and  bullying 
other  children,  in  teasing  and  in  ridiculing  them,  and  in  com- 
pelling their  submission.  These  acts  borrow  the  drive  of  the 
behavior  from  which  they  originate.  Submitting  to  coercion 
is  probably  developed  from  the  more  original  tendency  to 
seek  pain.  To  be  conspicuous  in  any  way,  as  when  wearing 
unusual  clothes  or  occupying  the  center  of  the  stage,  is  a  mod- 
ification of  the  tendency  to  exhibit  the  body. 

As  the  child  grows  older,  his  masterful,  submissive,  and 
exhibitionary  tendencies  conform  more  and  more  to  the  re- 
quirements of  this  world,  and  the  origin  of  these  tendencies 
is  obscured.  Sadism  plays  its  part  in  taking  people  to  prize 
fights,  in  causing  them  to  read  news  paper  atrocities  or  to 
punish  children,  and  in  a  more  useful  form  the  same  motive 
gives  drive  to  the  physician,  the  magistrate,  or  the  army 
officer.  Willingness  to  submit  to  pain  makes  men  tolerant  of 
the  imposition  practiced  on  them  by  those  they  love.  Derived 
from  exhibitionism  are  the  acts  of  having  one's  picture  taken, 
seeking  newspaper  publicity,  wearing  lodge  regalia,  crusading 
for  dress  reforms,  speaking  in  public,  or  running  for  political 
office. 


146  HUMAN  MOTIVES 

Conflict 

The  blocking  of  an  emotional  reaction  tendency,  combined 
with  the  absence  of  any  adequate  outlet,  is  called  a  conflict. 
When  a  conflict  arouses  an  unusual  amount  of  unliberated 
drive,  a  form  of  behavior  known  as  hysteria  may  result.  The 
symptoms  of  hysteria  are  sometimes  shown  in  relatively  futile 
acts,  more  or  less  suggestive  of  the  consummatory  act  which  is 
so  well  inhibited.  Thus  a  mother  who  has  lost  her  baby  may 
lavish  care  upon  flowers  or  household  pets.  More  frequently, 
however,  the  hysterical  symptom  is  an  act  which  serves  the 
same  purpose  as  the  act  which  is  inhibited.  For  example,  in 
Dr.  Ames'  case,  the  patient  who  could  not  bring  himself  to 
desert  his  wife  became  hysterically  blind  and  thus  succeeded 
in  being  removed  from  home.  It  should  be  borne  in  mind  that 
the  hysterical  act  or  symptom  is  beyond  the  patient's  control. 

A  persistent  tendency  to  perform  some  useless,  silly,  or 
distasteful  act  is  called  in  psychiatry  a  fixed  or  imperative 
idea.  This  is  seen  when  a  person  cannot  avoid  humming  to 
himself  a  haunting  melody  which  has  become  displeasing, 
when  the  effort  to  inhibit  obscene,  profane,  or  apparently  com- 
monplace words  persistently  fails,  or  when  a  distasteful  act 
is  repeatedly  the  final  outcome  of  mutual  inhibition.  The  re- 
enforcement  which  makes  such  acts  imperative  is  usually  a 
proprioceptive  mechanism,  such  as  sex  or  anger,  which  has  be- 
come linked  up  with  the  original  action  system  through  con- 
ditioning. The  fear  which  results  from  a  person's  imagining 
that  he  is  becoming  insane  serves  as  such  a  reenforcement, 
and  by  frequent  use  the  fear  of  insanity  increasingly  occupies 
the  mind.  When  the  reenforced  act  is  useful,  and  not  dis- 
pleasing to  the  subject,  its  frequent  occurrence  causes  no  anxi- 
ety and  is  never  thought  morbid,  although  the  drive  mech- 
anism may  be  the  same  as  in  the  case  of  a  fixed  idea. 

Forgetting  an  act  may  sometimes  be  due  in  part  to  the  in- 
hibition of  tendencies  with  which  the  act  has  become  associ- 


HUMAN  MOTIVES  147 

ated.2  Our  failure  to  remember  the  name  of  an  acquaintance 
may  be" the  simple  result  of  long  disuse,  but  if  speaking  the 
name  has  become  associated  with  inhibited  action  tendencies, 
the  word  threshold  is  further  raised  and  we  are  often  power- 
less to  recall  the  word. 

Dreams  correspond  to  reaction  tendencies  which  are  com- 
monly inhibited  in  waking  life.  In  sleep  the  inhibitions  are 
partly  removed  by  the  absence  of  certain  sensory  stimuli  which 
affect  us  when  awake.  Responses  are  prevented  by  the  resist- 
ance in  motor  conduction  paths. 

Undirected  by  any  very  rich  sensory  experience,  and 
partly  rid  of  inhibitions,  the  imagery  of  dreams  follows  the 
course  of  wish  fulfillment  in  a  way  unknown  to  waking 
thought.  Thus  our  dreams,  when  properly  interpreted,  reveal 
to  us  many  unsuspected  propensities.  In  this  way  dreams  be- 
come useful  material  in  the  detection  of  conflicts  in  hysterical 
subjects. 

Overcorrection 

One  of  the  richest  sources  of  the  stimuli  which  inhibit 
our  responses  is  the  social  sanction  of  our  fellows.  The  world 
demands  of  us  many  virtues  which  we  do  not  possess.  By 
simulating  such  virtues  as  we  lack,  and  so  disguising  our  in- 
most tendencies,  we  gain  approbation  and  escape  contempt. 
We  ourselves,  however,  are  never  wholly  deceived  by  the  sup- 
erficial artifices  which  we  substitute  for  the  more  spontaneous 
tendencies  observed  in  others.  In  our  effort  to  conform  to 
social  standards  we  frequently  overcorrect  for  our  faults,  so 
that  our  virtues  are  too  conspicuous  to  seem  real. 

Persons  who  laugh  loudest  at  the  Saturday  night  bath 
stories  are  likely  to  have  acquired  punctilious  bathing  habits 
late  in  life.  The  genealogical  bore  is  usually  a  man  of  humble 
origin  in  at  least  one  unstudied  line  of  descent.  Ostentatious 
modesty  is  impossible  in  any  one  who  is  not  immodest  at  heart. 
A  man  who  subscribes  himself  "very  sincerely"  should  be 

2  Many    instances    of    such    forgetting    are    described    in    Freud's    PgychopalhoJogy    of    Every 
Day  Life. 


148  HUMAN  MOTIVES 

watched.    It  is  a  fairly  safe  generalization  that  the  noisiest  re- 
formers all  possess  the  tendencies  which  they  spend  their  lives 

in  condemning. 

Play 

Compared  with  practical  conduct,  play  is  an  incomplete 
act  given  in  response  to  an  incomplete  situation.  It  will  be  re- 
membered that  a  situation  is  made  up  of  many  stimuli  and  that 
an  act  is  composed  of  many  combined  responses.  The  situa- 
tions to  which  the  young  are  exposed  are  almost  always  lack- 
ing in  stimuli  which  are  present  in  the  situations  which  con- 
front the  adult.  The  puppy's  antagonist  does  not  tear  the 
puppy's  flesh,  and  is  otherwise  less  aggressive  than  the  oppon- 
ent of  the  large  dog.  The  child's  doll-house  lacks  stairways, 
plumbing,  and  many  of  the  necessary  part  of  a  real  house.  The 
doll  itself  may  be  so  elaborated  as  to  close  its  eyes  or  squeak, 
but  it  is  grossly  lacking  in  the  characteristics  of  real  baby.  You 
sit  down  on  the  rug  and  say,  "Let's  play  that  this  is  a  boat." 
For  play  purposes  the  absence  of  naval  architecture  is  as  un- 
important as  the  absence  of  surrounding  water.  The  next  door 
neighbor  is  an  Indian  if  he  has  feathers  and  a  tomahawk,  even 
though  he  lacks  the  bloodthirstiness  of  the  actual  redskin. 

Just  as  the  play  situations  are  limited,  so  are  the  acts  of 
play  correspondingly  limited.  The  puppy  is  actuated  to  gentle 
aggression  and  limited  retreat,  whereas  a  richer  situation  with 
more  intense  stimuli  would  have  resulted  in  either  real  fight- 
ing  or  flight.  The  child's  doll-housekeeping  is  very  sketchy, 
and  her  care  of  the  doll  is  thoroughgoing  only  in  such  matters 
as  hugging  and  spanking.  The  child's  skill  in  handling  the 
rug-boat  would  never  qualify  him  as  a  real  navigator.  His  as- 
sault upon  the  Indian  next  door  is  fortunately  abortive,  and 
may  even  be  limited  to  saying  the  word  "bang." 

We  are  apt  to  say  that  the  child  fills  in  the  gaps  in  the  sit- 
uation by  imagination.  This  is  often  an  unjustified  interpreta- 
tion by  the  adult,  who  is  more  likely  than  the  child  to  notice 


HUMAN  MOTIVES  149 

the  gaps  and  to  interpret  the  fairy  story  or  to  people  the  mud 
pie  with  apples. 

Not  only  is  the  local  situation  incomplete,  but  there  is  an 
incomplete  apprehension  of  the  larger  situation.  The  cues  to 
distant  but  related  situations  which  occur  in  the  limited  play 
environment  are  overlooked.  For  this  reason  play  is  charac- 
terized by  the  low  stimulus  thresholds  which  are  present  with- 
in the  smaller  situation  and  which  are  due  to  the  absence  of 
inhibiting  and  facilitating  effects  of  more  distant  situations. 
There  is  involved  a  disregard  of  incongruities,  as  in  the  thea- 
tre when  the  background  is  a  canvas  drop  instead  of  a  prison 
wall,  and  when  the  orchestra  pit  would  offer  a  way  of  easy  es- 
cape for  a  real  prisoner.  Children  at  play  have  a  high  thres- 
hold for  the  summons  of  parents  but  a  very  low  one  for  the 
behavior  of  their  playmates.  Thus  play  situations  are  more  or 
less  isolated  from  the  world  as  a  whole.  The  player  is  detach- 
ed, irresponsible,  carefree.  Although  this  same  isolation  may 
at  times  seem  to  characterize  serious  work  as  well,  this  is  real- 
ly never  so,  work  always  being  controlled  by  remote  situations 
more  or  less  suggested  by  present  stimuli.  Freedom  from 
this  kind  of  facilitating  and  inhibiting  stimuli  accounts  for  the 
frequent  description  of  play  as  activity  without  external  com- 
pulsion, or  as  aimless  or  purposeless  activity.  Such  a  descrip- 
tion tacitly  assumes  that  work  requires  reenforcement  from 
associated  situations. 

In  the  nature  of  things  children  play  more  than  do  adults. 
If  they  react  at  all  to  a  limited  environment  it  must  be  with  a 
limited  response.  Play,  however,  is  not  lacking  in  adult  behav- 
ior. It  is,  of  course,  often  deliberately  planned.  In  athletic 
contests  and  games,  conventional  restrictions  inhibit  certain  of 
the  responses  of  participants,  and  so  limit  the  situation  to 
which  the  others  respond.  On  the  track  we  are  not  tripped 
up  or  pushed,  although  under  more  grim  conditions  this  would 
be  a  part  of  the  situation.  Our  opponent  at  tennis  does  not  at- 
tack us  with  his  racquet  and  our  boxing  partner  attacks  us 
only  with  his  gloves. 


150  HUMAN  MOTIVES 

Not  only  is  an  act  of  play  incomplete  when  compared  with 
the  movements  involved  in  serious  work,  but  the  play  act  con- 
tains many  movements  not  found  in  practical  life.  Probably 
the  most  conspicuous  of  these  superfluous  play  movements  is 
the  talking  which  is  nearly  always  a  part  of  make-believe  be- 
havior. In  playing'  "horse"  with  a  broomstick  a  child  will 
speak  to  the  object  in  a  way  which  would  be  useless  if  the  play- 
thing were  real.  He  will  explain  to  the  onlookers  imaginary 
characteristics  of  his  mount.  Moreover  he  substitutes  his  own 
locomotion  for  that  of  the  supposititious  animal.  The  horse's 
life  is  crowded  with  a  wealth  of  dramatic  incident  which  no 
actual  horse  would  tolerate. 

The  origin  of  the  extra  movements  of  play  is  to  be  looked 
for  first  in  the  necessity  which  the  child  faces  of  compensating 
for  the  sketchiness  of  his  playthings.  If  the  horse  is  unable 
to  pull  the  child,  the  child  must  pull  the  horse.  The  absence 
of  temper  in  the  wooden  animal  is  made  up  for  by  much  jerk- 
ing, shaking,  and  clinging  on  the  part  of  the  rider.  Other 
sources  of  superfluous  movement  are  emotional  expression, 
the  traditional  way  of  playing  such  and  such  a  game,  and  the 
habits  which  the  child  has  formed  in  somewhat  similar  situa- 
tions. 

Just  as  play  acts  contain  superfluous  movements,  so  the 
play  situations  contain  many  elements  not  found  in  the  prac- 
tical world.  This  is  so  because  the  child  is  obliged  to  use  make- 
shi  ft  toys  and  to  look  for  adventure  under  restricting  circum- 
stances. The  tail  of  the  broomstick  horse  is  made  of  straw.  Its 
travels  carry  it  over  rugs,  through  hallways,  and  up  the  stairs. 
Its  existence  is  spent  in  an  incongruous  world  and  may  at  any 
time  come  to  an  end  when  sweeping  begins. 

In  play  consummatory  responses  are  never  successfully 
expressed.  Tea  is  drunk  from  empty  cups.  The  slaughtered  en- 
emy is  soon  back  in  the  fight.  Kissing  games  are  supervised 
by  adult  chaperones.  In  short,  play  is  the  prolongation  of 
preparatory  responses,  the  consummatory  response  never  be- 


HUMAN  MOTIVES  151 

ing  sufficiently  complete  to  terminate  the  behavior.  Partial  re- 
sponses to  incomplete  sex  situations  occur  from  earliest  in- 
fancy. Before  the  baby  is  able  to  carry  on  a  successful  fight  he 
shows  anger,  and  fear  is  manifest  before  he  has  developed  the 
movements  necessary  to  flight.  The  incompleteness  of  con- 
summatory  responses  in  play  maintains  the  preparatory  re- 
sponses and  produces  a  high  pitch  of  emotional  excitement. 

The  energy  with  which  play  activities  are  carried  on  sug- 
gests at  once  their  reenforcement  from  internal  responses  such 
as  are  present  in  the  preparatory  acts  of  hunger,  love,  rage, 
and  fear.  With  the  beginning  of  play  any  lassitude  that  may 
have  been  evident  disappears.  In  dancing,  boxing,  and  the 
game  of  hide-and-seek  the  complete  response  is  aborted.  With 
the  proper  additions  to  the  situations  the  excitement  of  play 
may  be  increased  to  the  point  of  actual  love,  rage,  or  fear. 

It  follows  from  what  has  been  said  that  play  cannot  be  de- 
scribed as  a  specific  instinct,  nor  is  there  any  group  of  original 
response  tendencies  which  in  themselves  constitute  play.  Play 
is  almost  as  much  dependent  on  learning,  the  fixation  of  habits, 
and  the  organization  of  responses  about  objects  and  situa- 
tions as  are  the  serious  activities  of  adult  life. 


CHAPTER  7 

SOCIAL  PSYCHOLOGY 

Social  psychology  deals  with  the  concerted  behavior  of 
groups  of  individuals,  and  with  the  individual's  responses  to 
his  fellow  man. 

Fellow  Man  as  a  Constant  Situation 

We  pay  more  attention  to  people  than  to  any  other  part  of 
our  environment,  and  they  furnish  the  occasion  for  our  most 
elaborate  behavior.  The  complex  variety  of  their  activities 
calls  out  in  us  a  correspondingly  rich  assortment  of  responses. 
Conversely,  they  are  not  passive  objects,  but  are  possessed  of 
pent  up  tendencies  to  action  which  may  be  released  at  our 
slightest  intervention. 

Every  culture  presents  to  man  a  distinctive,  peculiar,  and 
individual  environment.  An  island  in  the  South  Seas  has  few 
resemblances  to  the  makeup  of  a  large  city.  The  food,  the  hab- 
itation, and  the  outdoor  life  of  the  Esquimaux  differ  greatly 
from  those  of  the  Louisiana  Negro.  Aside  from  such  univer- 
sal features  of  the  environment  as  light,  atmosphere,  gravita- 
tion, and  the  uniformity  of  nature  which  science  attempts  to 
describe,  the  one  thing  common  to  all  societies  is  fellow  man, 
his  anatomy  and  his  original  nature.  He  is  fairly  constant 
from  one  generation  to  another  and  fundamentally  the  same 
in  all  localities.  For  this  reason  there  is  an  obvious  fitness  and 
propriety  in  the  fact  that,  no  matter  where  we  may  be  born  or 
who  we  may  be,  we  respond  to  him  with  many  instincts  and 
habits  common  to  humanity.  He  has  always  been  the  neces- 
sary object  when  we  nurse  as  babies  or  love  as  adults.  He  is 
essential  to  our  conversation  and  our  quarrels.  Without  him 
we  could  not  steal,  murder,  or  disturb  the  peace.  In  his  child- 
hood he  actuates  us  to  nurse,  shelter,  and  protect  him.     In 

(152) 


SOCIAL  PSYCHOLOGY  153 

short,  because  of  his  invariable  structure,  conduct  toward  him 
shows  a  persistent  similarity  in  all  societies. 

Other  Prevalent  Situations 

Gravity,  the  earth's  surface  as  a  dwelling  place,  rain, 
sun,  day,  night,  and  the  seasons,  are  relatively  changeless  situ- 
ations in  the  history  of  the  race.  Vegetation,  animal  neighbors, 
and  the  sources  of  food,  though  somewhat  the  same  in  every 
epoch  and  every  climate,  show  more  variability.  Houses,  ve- 
hicles, tools,  highways,  industries,  superstitions,  ceremonies, 
recreations,  language,  and  human  institutions  in  general,  char- 
acterize particular  times  and  places.  According  as  these  situ- 
ations are  generally  met  with,  a  similarity  of  habits  is  estab- 
lished in  all  members  of  society.  The  possession  of  common 
habits  is  what  distinguishes  a  society  from  a  mere  aggregate 
of  people.  It  is  our  task  to  discover  the  situations  which  ac- 
complish this  unification  of  response.  Although  the  history 
of  social  machinery  is  the  legitimate  subject  matter  of  sociol- 
ogy, man's  creation,  acceptance,  and  rejection  of  the  artificial 
forms  of  society  is  a  question  for  psychology. 

People  show  great  similarity  of  behavior  toward  all  ob- 
jects commonly  met  with.  They  sit  in  response  to  chairs,  sleep 
in  beds,  ride  on  trains,  hoard  money,  distrust  strangers,  and 
wear  clothes.  There  are  other  objects  toward  which  the  world 
as  a  whole  does  not  respond  so  uniformly.  Christians  have  a 
particular  way  of  acting  toward  the  Bible,  Americans  toward 
their  flag,  women  toward  jewelry,  the  voodoo  worshipper  to- 
ward his  fetish,  certain  groups  toward  their  totems,  and  each 
household  toward  its  belongings.  The  possession  of  similar 
response  tendencies  toward  these  objects  defines  and  unifies  a 
group. 

Places,  like  objects,  elicit  characteristic  responses  in  the 
group.  There  is  a  conduct  proper  to  church,  to  the  dining- 
room,  the  graveyard,  the  schoolroom,  the  ball  park.  Appro- 
priate dress  on  the  bathing  beach  is  inappropriate  on  the  street 


1 54  SOCIAL  PSYCHOLOGY 

car.  While  in  a  conveyance  that  moves  vertically  we  remove 
our  hats,  but  when  in  one  that  moves  horizontally  we  feel  no 
compulsion  to  do  so. 

Times,  like  places  and  objects,  stimulate  us  all  to  common 
action.  We  work  by  day  and  sleep  by  night;  we  show  good 
will  toward  men  on  Christmas  and  ill  will  on  Halloween ;  we 
are  boisterous  on  July  Fourth  and  sedate  on  Sunday.  We 
glance  at  the  clock  and  sav  it  is  time  for  the  children  to  be  in 
bed,  or  again  we  say  it  is  time  to  get  up.  There  is  a  usual 
time  for  tea,  vacations,  and  formal  calls.  Birthdays,  festivals, 
weddings,  funerals,  puberty  ceremonies,  and  harvest  time  all 
demand  their  particular  observances,  and  unconventional  be- 
havior is  on  such  occasions  regarded  as  improper. 

We  respond  in  a  characteristic  way  to  people  recognized 
as  belonging  to  certain  classes.  We  reserve  deference,  affabil- 
ity, or  generosity  for  some,  and  arrogance,  contempt,  right- 
eous indignation,  or  fear  for  others.  Thus  toward  servants, 
policemen  in  uniform,  royalty,  the  graybearded,  our  betters, 
negroes,  clergymen,  prostitutes,  blood-relatives,  parents,  crim- 
inals, reds,  radicals,  women,  and  children  we  acquire  distinct 
and  conventionally  organized  responses. 

The  efficiency  of  words  depends  upon  their  arousing  simi- 
lar reactions  in  everyone.  Some  words,  like  some  places,  ob- 
jects, times,  and  classes  of  people,  provoke  not  only  a  con- 
ventional response  but  arouse  along  with  it  an  emotional  drive 
which  is  particularly  effective  in  unifying  the  crowd.  The 
shrewd  orator  can  rouse  in  his  audience  shame,  awe,  anger, 
pride,  fear,  or  pity,  by  the  proper  choice  of  words  or  phrases, 
or  by  employing  a  particular  tone  of  voice.  "Americanism," 
"gentlemanly,"  "honorable,"  "profiteer,"  "hell,"  are  examples 
of  drive  arousing  words.  Titles  are  valued  because  they  com- 
mand respect.  "Sir,"  "Captain,"  "doctor,"  "professor,"  are 
titles  which  often  carry  an  unmerited  prestige.  Academic  de- 
grees may  be  sought  as  an  end  in  themselves.  Children  hang 
their  heads  when  told  that  they  are  "naughty,"  regardless  of 


SOCIAL  PSYCHOLOGY  155 

what  they  have  done.  Political  catchwords  stir  up  enthusiasm 
without  much  dependence  upon  their  literal  significance,  and 
obscene  words  always  secure  the  attention  of  polite  people. 

Formation  of  Habits  in  Common 

The  formation  of  common  habits  in  a  group  is  due  to  im- 
itation and  other  forms  of  conditioned  response  and  to  adapta- 
tion. Given  the  proper  environment,  society  as  a  whole  may 
form  almost  any  habit  which  it  is  possible  for  the  individual 
to  acquire.  Outlandish  customs  are  not  the  fruit  of  anomalies 
of  human  nature  in  strange  peoples,  but  merely  the  growth 
of  a  social  inheritance  guided  by  the  strange  world  in  which 
they  live. 

Properly  regulated  behavior  in  a  community  involves 
something  more  than  mere  similarity  of  response  among  the 
individuals  concerned.  There  is  always  to  be  found  another 
sort  of  unity  of  action  which  may  be  called  complementary  be- 
havior. The  way  in  which  mother  and  child  secure  best  results 
is  not  to  behave  alike  but  to  behave  differently.  A  mother 
acts  in  much  the  same  way  as  mothers  in  general,  and  a  child 
learns  the  way  of  children.  Thus  commonality  of  behavior  at- 
taches to  classes  of  persons,  but  the  proper  interplay  of  re- 
sponses of  two  persons  of  different  classes  necessitates  not 
similar  but  reciprocal  conduct.  Indeed,  cooperation  between 
any  two  individuals  demands  conplementary  as  well  as  like  re- 
sponses. Officer  and  enlisted  man,  physician  and  patient,  mer- 
chant and  customer,  master  and  servant,  teacher  and  pupil, 
husband  and  wife,  lawyer  and  client,  each  acts  according  to 
his  conventional  part  in  the  relationship,  but  not  necessarily 
in  the  same  way  as  the  person  with  whom  he  is  holding  social 
intercourse. 

In  the  case  of  groups,  as  in  the  case  of  individuals,  a  habit 
response  originally  given  to  one  situation  may  later  be  given  to 
another  situation,  due  to  the  similarity  or  partial  indentity  of 
the  two.  A  parent  learns  to  discipline  his  child  and  the  child 


1 56  SOCIAL  PSYCHOLOGY 

to  obey  his  parent,  and  later,  when  the  child  becomes  an  adult, 
this  coercive  and  submissive  relation  persists  and  is  often  det- 
rimental to  good  government  in  the  tribe.  The  "rule  of  the 
elders"  in  primitive  culture  depends  upon  this  undue  pertina- 
city of  children's  habits  of  obedience  and  parents'  habits  of 
domineering,  and  involves  a  limitation  of  liberty  for  the  young 
and  an  extension  of  privilege  for  the  old. 

The  treatment  of  the  dead  depends  upon  the  persistence 
of  habits  formed  toward  the  living.  The  name,  the  personal 
belongings,  and  the  dwelling  place  of  a  deceased  friend  call 
out  responses  which  are  wholly  inappropriate  when  he  is  gone. 
So,  until  these  habitual  responses  of  the  survivors  are  dissipat- 
ed, his  ghost  still  walks.  Weapons  are  put  in  his  coffin  and  food 
is  placed  upon  his  grave.  His  name  is  spoken  with  caution  and 
only  his  virtues  are  mentioned,  lest  he  overhear.  If  he  was 
a  headman  or  chief  there  still  adheres  to  his  sword  some  of 
his  valor  which  makes  the  weapon  deadly,  and  his  mantle  gives 
to  his  successor  a  contagious  wisdom. 

The  sentimental  value  of  belongings,  the  attachment  we 
show  to  places  in  which  we  have  spent  happy  days,  the  thrill 
aroused  by  the  name  of  someone  we  love,  are  all  due  to  the 
former  presence  of  situations  in  which  these  symbols  were  in- 
cidental features.  The  power  of  the  symbols  to  call  out  these 
conditioned  emotional  responses  makes  men  more  willing  to 
pay  taxes  on  their  homes  and  gives  men  a  common  interest  in 
the  symbolism  of  art,  drama,  and  fiction.  The  transfer  of  re- 
sponse to  substituted  stimuli  may  also  be  due  to  a  mere  similar- 
ity between  the  new  stimuli  and  the  old.  It  is  hard  for  us  to 
mutilate  the  photograph  of  a  friend  even  though  we  realize 
that  it  is  a  mere  bit  of  paper.  Because  women  have  learned 
to  call  little  children  "cute"  or  "dear,"  any  object  which  is  a 
miniature  duplicate  of  something  usually  seen  in  large  size  is 
apt  to  be  described  in  these  words.  We  hear  such  expressions 
as,  "What  a  dear  little  house,"  "What  cute  little  biscuits."  The 


SOCIAL  PSYCHOLOGY  157 

smallest  entry  in  the  dog  show  always  has  an  attentive  femin- 
ine audience. 

In  childhood  many  responses  are  organized  around  hum- 
an beings  and  are  later  given  to  situations  in  which  fellow  man 
does  not  figure.  Children  learn  to  seek  their  parents'  protec- 
tion when  in  danger,  or  their  assistance  when  in  trouble.  Par- 
ents and  playmates  often  interfere  with  children's  undertak- 
ings, and  children  learn  to  overcome  this  interference  with 
supplicating,  placating,  and  ingratiating  behavior,  with  plaus- 
ible excuses  for  misconduct,  or  by  sharing  their  possessions 
with  these  older  and  stronger  companions.  When  the  child 
grows  up,  due  to  the  tenacity  of  early  habit,  he  often  responds 
in  a  childish  way  to  danger,  pain,  sickness,  misfortune,  ridi- 
cule, loneliness,  or  failure. 

If  he  is  a  benighted  savage,  he  may  not  realize  that 
sometimes  inanimate  nature  alone  is  responsible  for  his  mis- 
fortune, and,  seeing  no  human  cause  in  the  situation,  may  make 
up  for  its  absence  by  inventing  or  by  accepting  as  present  the 
evil  spirits,  demons,  fays,  and  goblins  that  are  part  of  all  sav- 
age superstition.  These  he  placates  in  childish  fashion  by  ges- 
ture, cringing  posture,  words  of  praise,  promises  of  good  con- 
duct, circumspect  behavior,  and  the  offering  of  sacrifice.  Be- 
cause the  storm  wind  is  destructive  he  assumes  it  to  have  a  per- 
sonality. The  dangerous  waterfall,  the  unsealed  mountain, 
he  treats  as  he  would  treat  mighty  human  beings.  When 
plague,  sickness,  drought,  famine,  flood,  shipwreck,  invasion, 
or  other  misfortune  occurs,  the  tribe  as  a  whole  appeal  to  the 
spirits  of  their  ancestors  or  to  graven  images  for  the  assist- 
ance which,  as  children,  they  had  learned  to  expect  from  par- 
ents. 

The  combined  appeal  to  the  spirits  is  often  supposed  to 
be  answered  by  a  sign  or  augury.  This  gives  confidence  to  the 
idolaters  that  they  will  be  saved,  and  there  results  such  a  prac- 
tical good  as  the  passing  of  fear  or  the  unification  of  group 
effort  in  meeting  the  misfortune.    This  persistence  of  childish 


1 58  SOCIAL  PSYCHOLOGY 

reactions  in  the  group  makes  fertile  ground  for  the  growth  of 
certain  vocations  connected  with  ceremony,  divination,  magic 
and  sacrifice.  Thus  there  are  found  groups  of  professional 
conjurers,  magicians,  medicine  men,  priests,  and  augurs  who 
select  and  organize  the  ritual  of  festivals,  incantation  ceremo- 
nies, and  temple  life. 

In  our  own  civilization  childish  responses  in  the  face  of 
danger  or  misfortune  are  by  no  means  lacking.  The  adult 
male,  his  early  tendencies  to  depend  on  nurse  or  mother  long 
overlaid  by  habits  of  practical  self  reliance,  will,  when  sick 
and  taken  to  the  hospital,  exercise  again  his  infantile  re- 
sponses. He  tolerates  with  considerable  satisfaction  the  per- 
sonal service  of  his  nurse,  querulously  demands  attention,  is 
jealous  of  other  patients,  becomes  fretful  upon  small  provoca- 
tion, and  is  pleased  by  trifles. 

Language  includes  names  for  many  wholly  mythical 
situations,  and  society  may  react  to  these  names  as  though  the 
situations  were  real.  In  order  to  explain  the  fact  that  these 
situations  fail  to  stimulate  sense  organs  the  believer  calls  them 
immaterial,  disembodied,  incorporeal,  astral,  intangible,  invis- 
ible, shades,  or  ghostly  shadows,  although  such  words  afford 
no  real  explanation.  The  happy  hunting  ground  and  the  Mos- 
lem paradise  may  conceivably  be  beyond  the  reach  of  our  sense 
organs  because  of  their  great  distance,  but  it  requires  more  ex- 
planation to  make  plausible  living  beings  which  may  work 
good  or  evil  in  a  physical  world,  but  which  cannot  affect  the 
organs  of  vision  or  touch.  The  ghost  in  the  dark  is  the  fright- 
ened person's  rationalization  of  his  fright;  the  evil  spirit  is 
the  unfortunate's  rationalization  of  his  bad  fortune;  just  as 
the  careless  person  explains  the  loss  of  a  misplaced  article  by 
saying  that  a  thief  must  have  taken  it,  or  just  as  the  farmer 
explains  the  cool  breeze  in  summer  by  saying  that  hail  must 
have  fallen  in  the  vicinity. 

There  is  a  tribe  of  Sioux  north  of  Edmonton  who  believe 
in  the  existence  of  a  beast  which  has  a  convenient  way  of  mak- 


SOCIAL  PSYCHOLOGY  159 

ing  itself  invisible  when  looked  at.1  Many  Indians  have  been 
pursued  by  it  along  forest  trails  after  dusk,  to  fall  exhausted 
at  the  outskirts  of  the  village.  Similar  beings  rattle  tambou- 
rines, write  on  slates,  move  tables,  and  speak  through  the  lips 
of  mediums.  If  the  credulous  Indian  or  the  devotee  of  spir- 
itism is  asked  why  these  odd  beings  do  not  perform  in  the  sun- 
light, he  takes  refuge  in  the  answer  that  it  is  the  nature  of  the 
creatures  to  live  in  darkness.  The  influence  of  unseen  spirits 
was  the  fundamental  doctrine  of  witchcraft;  it  explained  to 
our  forefathers  the  eccentric  behavior  of  the  insane,  and  even 
now  is  used  by  the  uneducated  to  account  for  the  tricks  of  the 
professional  clairvoyant.  As  the  Indian's  flight  from  the  noise 
in  the  dark  is  exactly  the  same  as  his  flight  would  be  from  such 
a  beast  as  the  tribe  has  talked  about,  a  noise  has  for  him  all 
the  meaning  that  a  real  beast  would  have.  In  so  far  as  the 
old  dupe  gives  the  same  emotional  response  to  his  dead  son's 
name  on  the  lips  of  the  medium,  or  to  an  alleged  message  writ- 
ten on  a  slate,  that  he  would  give  to  the  son's  presence,  the 
situation  seems  real  to  him.  When  we  consider  the  ease  with 
which  an  individual  may  fall  victim  to  a  belief  in  unrealities, 
though  modern  scientific  method  is  at  his  disposal  for  checking 
up  his  belief,  it  is  not  surprising  that,  in  cultures  lacking  the 
methods  of  science,  credulity  for  erroneous  tradition  should 
be  the  rule. 

One  result  of  society's  conforming  to  manners  and  cus- 
tom is  that  thereby  men  are  able  to  react  not  only  to  what  their 
neighbors  have  done  but  also  to  what  they  are  about  to  do. 
This  simplifies  the  world  and  makes  life  in  communities  pos- 
sible. The  amenities  of  polite  society  expedite  our  taking 
leave  of  our  hostess,  make  ponderous  explanations  of  our  com- 
ings and  goings  unnecessary,  and  prevent  much  of  the  ill  feel- 
ing which  a  candid  analysis  of  situations  would  produce.  Sim- 
ilarity of  custom  produces  solidarity  within  a  social  group. 
The  strangeness  of  contrasting  custom  seen  in  outsiders  em- 
phasizes caste  and  prevents  the  cohesion  of  diverse  classes. 

1  Eeported  by  Mr.   W.  D.   Wallis. 


160  SOCIAL  PSYCHOLOGY 

The  Spread  of  Tradition 

Tradition  is  the  transmitted  directions  for  dealing  with 
situations.  Through  the  instrumentality  of  words  we  may  be 
properly  prepared  for  events  which  we  have  not  before  ex- 
perienced. Both  common  sense  and  science  have  this  function, 
and  tell  us  what  to  expect  of  objects  and  people.  Applied 
science  includes  the  description  of  the  effects  of  situations  on 
society.  Knowledge  is  passed  down  to  us  concerning  what 
plants  are  poisonous,  what  to  do  when  we  wish  to  cross  a 
river,  when  to  plant  corn,  the  way  to  trap  animals,  the  kind 
of  weather  that  is  likely  to  follow  an  east  wind,  or  how  to  in- 
sure good  luck. 

Morality  consists  of  traditional  directions  for  conduct,  re- 
enforced  by  social  coercion.  This  coercion  is  accomplished 
not  only  by  force  but  by  approval  and  disapproval,  praise,  and 
censure,  friendliness  and  hostility.  To  the  expression  in  word 
and  action  of  these  emotions  in  others  we  ourselves  give  emo- 
tional responses.  It  is  these  emotions  in  us  which  constitute  the 
drive  toward  moral  conduct. 

Approach  and  avoidance  responses  have  their  analogues 
in  the  vocabulary  of  morals;  and  the  words  good  and  bad, 
right  and  wrong,  brave  and  cowardly  are  stimuli  to  which  we 
learn  to  respond  in  early  childhood.  Although  social  presure 
is  necessary  for  the  original  establishment  of  morals,  when  the 
moral  habit  is  formed  it  acts  in  the  absence  of  coercion.  We 
do  not  read  another's  postcard  when  we  are  alone  because  we 
have  learned  to  avoid  doing  so  while  in  the  presence  of  others. 
The  habit  is  reenforced  by  the  words  which  we  have  heard  ap- 
plied to  this  ungentlemanly  act.  The  student  will  find  many 
interesting  examples  of  moral  tradition  and  moral  habit  in  the 
anthropological  literature  concerning  tabu.  Morals  are 
(aught  by  anecdote  and  fiction  as  well  as  by  precepts,  proverbs, 
golden  rules,  and  commandments.  The  words  of  the  anecdote 
suggest  the  situation  and  arouse  the  emotions  which  govern 
the  moral  response.    In  this  way  fables  and  stories  become  the 


SOCIAL  PSYCHOLOGY  161 

common  heritage  of  society  and  usually  involve  the  ambival- 
ence of  hero  and  villain. 

Traditions  are  built  up  through  use.  Temporary  fads  in 
conduct  are  absorbed  into  the  teaching  of  society  when  they 
are  fit,  and  eliminated  when  unfit.  Even  though  aided  by  this 
process  of  selection,  tradition  is  always  old-fashioned  and  lags 
somewhat  behind  practical  needs.  Only  after  words  are  coined 
for  new  predicaments,  and  these  words  have  wide  acceptance, 
is  it  possible  for  tradition  to  operate. 

An  individual's  opinion  includes  some  traditions  but  not 
others.  It  also  includes  a  statement  of  facts  based  upon  his 
own  experience.  Thus  opinion  is  built  up  from  suggestion 
and  from  induction.  It  is  usually  impossible  for  the  individ- 
ual to  experiment  in  the  various  sciences,  so  that  he  is  forced 
to  depend  upon  the  statements  of  others  for  many  of  his  views. 
Whether  he  accepts  the  unscientific  statements  of  laymen  or 
the  conclusions  of  experts  depends  but  little  upon  the  intrinsic 
merit  of  their  assertions.  Statements  are  likely  to  be  accepted 
which  reenforce  emotionally  colored  opinions  already  held,  or 
which  are  uttered  in  such  surroundings,  by  such  persons,  or  in 
such  words  as  arouse  reenforcing  emotions.  Acceptance  is 
inhibited  when  the  statements  oppose  existing  beliefs,  or  when 
the  situation  in  which  they  are  heard  arouses  emotional  re- 
sistance. 

Thus  individual  opinion  may  include  belief  in  erroneous 
causes  due  to  the  acceptance  of  tradition  outside  the  domain 
of  science.  In  this  way  superstitions  result  from  the  borrow- 
ing of  opinions.  These  "idola  theatri'"  may  have  widespread 
acceptance  and  pernicious  social  effects.  People  believe  in  the 
unlucky  nature  of  Friday,  or  of  the  number  13;  they  even  ac- 
cept the  divine  right  of  kings,  and  the  efficacy  of  homeopathic 
medicines,  of  amulets,  of  rain-making  ceremonies,  and  of 
"character  analysis." 

When  we  utter  an  opinion,  we  usually  do  so  in  response 
to  a  listener.  He  may  be  a  friend  or  an  enemy,  a  sweetheart 
or  a  rival,  an  employer  or  a  servant,  a  guest  or  an  insurance 


162  SOCIAL  PSYCHOLOGY 

agent.  Our  audience  may  be  a  crowd  of  one  kind  or  another, 
a  congregation,  a  college  class,  or  a  political  meeting.  The 
words  we  say  are  always  in  part  determined  by  the  character 
of  the  listener. 

What  we  say  is  further  determined  by  the  thresholds  of 
our  verbal  response  tendencies.  We  have  low  thresholds  for 
certain  truth  telling  and  for  certain  lying.  We  have  high 
thresholds  for  other  statements,  both  true  and  false.  That 
which  "occurs"  to  us,  whether  it  be  expressed  or  inhibited,  is 
a  statement  whose  threshold  is  low.  It  usually  describes 
things  as  we  wish  them  to  be,  and  is  always  designed  to  elicit 
from  society  a  response  which  we  desire.  We  have  a  low 
threshold  for  saying  that  the  runner  of  the  home  team  is  safe 
on  first,  no  matter  whether  this  is  true  or  false.  The  lonely 
child  in  bed  has  a  low  threshold  for  making  the  statement  that 
he  is  thirsty,  because  this  brings  him  temporary  companion- 
ship. High  thresholds  attach  to  admitting  that  our  family  is 
of  lowly  origin  or  subject  to  insanity,  to  telling  our  hostess 
that  we  have  had  a  tedious  evening,  or  to  using  profane  lang- 
uage. 

At  times  customary  inhibitions  to  speech  are  removed, 
and  unusual  facilitations  enter  into  the  situation.  During  a 
war,  a  political  capaign,  or  a  class  conflict,  partisan  feeling 
and  hostility  toward  opponents  drive  us  to  inaccurate  expres- 
sion and  weaken  many  old  inhibitions.  It  his  appeal  to  the  jury 
the  attorney  makes  biased  statements,  and  in  the  heat  of  elo- 
quence the  orator  often  garbles  the  truth. 

The  responses  of  the  listener  are  likewise  determined  by 
the  habits  he  has  formed,  as  well  as  by  the  external  situation. 
He  has  tendencies  to  accept  some  statements  and  to  reject  oth- 
ers. The  tendency  to  act  upon  or  to  repeat  the  assertions  of 
others  is  called  suggestibility,  and  when  these  assertions  are 
false  it  is  called  credulity.  The  listener,  like  the  speaker,  is 
affected  by  partisan  movements,  and  his  suggestibility  is  modi- 
fied accordingly.  He  is  credulous  of  slander  concerning  polit- 
ical enemies  and  of  eulogy  of  his  leaders.    Many  Englishmen, 


SOCIAL  PSYCHOLOGY  163 

but  no  Germans,  believed  a  report  that  St.  George  led  a  Brit- 
ish detachment  to  victory  in  one  of  the  engagements  of  the  late 
war. 

Opinion  Spreads  from  Hand  to  Mouth 

Where  the  subject  matter  is  outside  the  field  of  common 
sense,  and  thus  not  controlled  by  a  common  habit  of  statement 
in  the  group,  or  where  common  habits  are  disrupted  by  newly 
acquired  social  prejudice,  a  statement  of  alleged  fact  under- 
goes successive  modificattions  as  it  is  passed  on  from  speaker 
to  speaker.  The  cumulative  error  which  increasingly  attaches 
to  the  story  is  a  product  of  the  uninhibited  reaction  tendencies 
of  the  successive  narrators.  A  story  so  embellished  is  called 
a  rumor. 

An  act  cannot  be  imitated  by  anyone  who  has  not  formed 
habits  of  acting  in  a  like  way.  Inaccurate  imitation  results 
when  this  habit  is  not  quite  the  same  as  the  observed  act  which 
is  the  stimulus  to  imitation.  This  fact  is  illustrated  by  a  sim- 
ple experiment.  Write  five  digits  such  as  48275  on  a  card.  Se- 
lect a  number  of  subjects  and  have  the  first  one  copy  the  writ- 
ing on  another  card.  Have  the  second  reproduce  the  copy 
made  by  the  first,  the  third  the  copy  made  by  the  second,  and  so 
on  serially  through  the  group.  The  digits  written  by  the  last 
subject  will  probably  be  48275,  although  the  form  and  size  of 
the  digits  will  be  considerably  altered.  Now  make  a  nonsense 
drawing  of  random  lines  and  have  it  serially  transcribed  by 
the  same  subjects.  A  comparison  of  the  original  drawing  with 
the  final  transcription  will  show  very  little  likeness.  The  rea- 
son that  the  digits  are  reproduced  throughout  with  fair  ac- 
curacy is  that  all  the  subjects  possess  in  common  the  habitual 
response  of  writing  these  symbols.  The  cumulative  error  in 
the  serial  transcription  of  the  nonsense  drawing  is  due  to  the 
absence  of  any  common  habit.  The  modification  of  opinion  as 
it  is  passed  from  one  person  to  another  is  greatest  when  its 
expression  is  not  a  common  habit  in  the  group.  Myth  build- 
ing occurs  in  essentially  the  same  way.     The  myth  grows  as 


164  SOCIAL  PSYCHOLOGY 

generations  of  narrators  add  to  the  account  the  expression  of 
their  own  wishes.  Through  much  addition  and  nitration  its 
final  form  is  a  composite  story  voted  on  by  many  auditors. 

Human  Institutions 

The  foregoing  discussion  has  dealt  chiefly  with  shared 
environments  which  regulate  in  society  behavior  that  would 
otherwise  be  dispersed  and  uncooperative.  Original  nature,  as 
well  as  a  commonly  experienced  world,  furnishes  all  men  with 
tendencies  to  act  alike.  Of  these  tendencies,  the  emotional  ex- 
pressions, depending  only  in  part  upon  training  for  the  order 
and  the  composition  of  their  elements,  are  the  most  elaborate 
of  our  instinctive  behavior  patterns.  Common  group  habits 
associated  with  emotional  expressions,  such  as  flight,  repulsion, 
curiosity,  pugnacity,  subjection,  self-assertion,  parental  care, 
reproduction,  gregariousness,  acquisition,  and  construction, 
are  often  called  "instincts."  Although  they  are  habits  and  not 
instincts,  they  are  acquired  by  everyone  due  to  the  similarity 
of  environment  in  which  all  men  are  reared.  Given  our  reper- 
toire of  natural  response  tendencies  and  a  world  order  such  as 
we  have  all  lived  in,  our  instincts  inevitably  combine  with 
certain  emotional  expressions  to  form  these  almost  univer- 
sally shared  habit  patterns. 

Sociologists  and  others  often  attempt  to  explain  all  human 
conduct  in  terms  of  a  selected  few  of  these  coenotropes.  It  is 
then  that  the  danger  of  naming  these  patterns  "instincts"  and 
the  necessity  of  challenging  such  an  error  are  made  evident. 
Freud's  "libido,"  Le  Bon's  "suggestion,"  Tarde's  "imitation," 
Trotter's  "gregariousness"  and  Veblen's  "instinct  of  work- 
manship" are  all  vague,  unanalyzed  forces  which  drive  men  to 
action.  Even  when  these  widespread  habit  patterns  are  cor- 
rectly analyzed  and  clearly  defined  they  furnish  a  wholly  in- 
adequate description  of  human  motives. 

They  are  at  best  rough  and  convenient  terms  which  we 
use  to  portray  conduct,  but  each  of  them  applies  to  many  forms 


SOCIAL  PSYCHOLOGY  165 

of  conduct  of  diverse  origin,  and  all  of  them  taken  together 
fall  short  of  describing  the  majority  of  the  acts  of  every  day 
life. 

Human  institutions  are  social  habits  maintained  and  di- 
rected by  the  material  equipment  which  is  used  in  their  exer- 
cise. Banking,  commerce,  manufacturing,  agriculture,  trans- 
portation, language,  education,  slavery,  marriage,  war,  the 
state,  the  church,  the  theatre,  and  the  press,  all  have  their  pe- 
culiar tools,  and  are  established  not  only  in  custom  but  in  legis- 
lation as  well.  It  is  futile  to  attempt  a  description  of  the  origin 
and  maintenance  of  any  one  of  these  human  institutions  in 
terms  of  component  instincts,  emotions  or  coenotropes.  The 
institutions  are  too  complex  to  permit  such  analysis.  Although 
certain  emotions  obviously  predominate  in  some,  to  stress 
these  prevailing  emotions  is  likely  to  obscure  the  fact  that 
nearly  all  man's  capacities  are  involved  in  each  one. 


CHAPTER  8 
CONSCIOUSNESS 

When  two  men  are  stung  by  a  bee  an  observer  might  de- 
scribe both  events  in  the  same  way.  But  if  the  observer  hap- 
pens to  be  one  of  these  two  men,  he  will  describe  the  two  events 
differently.  In  a  way  this  is  not  surprising,  as  his  eyes  have 
witnessed  the  stinging  of  his  fellow  and  his  cutaneous  sense 
organs  have  witnessed  the  stinging  of  himself.  Because  those 
of  his  sense  organs  affected  when  he  himself  is  stung  are  dif- 
ferent from  those  affected  when  another  is  stung,  his  re- 
sponses to  the  two  situations  are  very  different. 

Almost  any  man  will  say  that  the  description  of  his  be- 
havior by  another  overlooks  certain  facts  in  the  case.  He  will 
say  that  he  knows  more  about  the  events  which  constitute  his 
own  life  than  any  one  else  knows.  And  he  may  say  that  the 
difference  between  being  stung  and  seeing  another  stung  is 
not  entirely  reducible  to  the  difference  in  the  sense  organs  af- 
fected and  the  responses  evoked. 

A  description  of  mind  in  terms  of  stimulation,  neural  ac- 
tion, and  responses  is  by  no  means  the  only  one  in  use.  There 
is  another  language  which  the  individual  may  employ  in  de- 
scribing the  world  as  his  own  experience,  and  which  includes 
terms  that  are  useless  in  a  description  of  behavior.  This  is 
the  language  of  consciousness,  and  its  importance  is  establish- 
ed by  its  popularity.  Its  terms  often  convey  a  meaning  whose 
expression  would  be  very  elaborate  if  attempted  in  the  lang- 
uage of  behavior. 

Every  man's  behavior  includes  conversation  about  his 
consciousness  though  his  consciousness  is  not  open  to  the  ob- 
servation of  others.  In  seeking  information  about  his  private 
consciousness  he  employs  the  method  of  introspection,  namely 
a  minute  description  of  his  experience  as  he  knows  it  at  the 

(166) 


CONSCIOUSNESS  167 

time.  The  introspector  may  report  in  some  such  way  as  this : 
"The  hunger  pang  seems  to  be  located  in  ly  stomach;"  or, 
"The  feeling  of  being  about  to  say  'yes'  involves  less  excite- 
ment than  the  feeling  of  being  about  to  say  'no' ;"  or,  "I  have  a 
clearer  memory  of  the  visual  appearance  of  digits  than  of  the 
visual  appearance  of  letters." 

Viewed  as  behavior,  introspection  is  usually  made  up  of 
verbal  responses  to  organic  states,  and  these  responses  are 
often  indicative  of  what  is  taking  place  in  the  body.  The  hun- 
ger pang  is  actually  coincident  with  a  peristaltic  contraction  of 
the  stomach.  The  consciousness  of  excitement  is  usually  coin- 
cident with  demonstrable  changes  in  pulse,  respiration,  and 
muscle  tone.  It  is  probable  that  a  clear  memory  for  digits  is 
coincident  with  cortical  action  corresponding  to  a  part  of  the 
cortical  process  which  takes  place  when  the  digits  are  being 
read. 

For  successful  introspection,  the  thresholds  of  the  verbal 
responses  must  be  made  unusually  low  by  excluding  distrac- 
tions and  by  providing  the  subject  with  directions  for  self 
observation. 

Because  men  use  the  language  of  consciousness  all  in 
much  the  same  way,  it  is  possible  for  us  to  assume  conscious- 
ness as  a  fact  and  to  construct  a  science  which  describes  it. 

The  science  of  consciousness  is  less  exact  and  less  useful 
than  the  science  of  behavior,  and  for  this  reason  the  science  of 
behavior  is  the  fundamental  description  of  psychological  facts. 
Nevertheless,  the  science  of  consciousness  is  an  interesting 
part  of  psychology  and  it  is  the  language  of  consciousness  that 
we  shall  now  use. 

Consciousness  and  the  Nervous  System 

Consciousness  is  supposed  to  occur  only  when  there  is 
nervous  action  in  certain  parts  of  the  cortex.  The  kind  of 
consciousness  which  occurs  depends  upon  the  part  of  the  cor- 
tex which  is  active.    Destruction  of  the  visual  cortical  area  re- 


168  CONSCIOUSNESS 

suits  in  the  loss  of  all  visual  sensations,  and  destruction  of 
other  sensory  areas  brings  about  a  corresponding  anaesthesia. 
Having  conscious  memories  and  ideas  requires  that  certain 
parts  of  the  cortex  shall  be  intact.  A  decerebrate  dog  has 
presumably  no  sensations,  thoughts,  or  feelings. 

Sensation 

If  we  analyze  consciousness  into  its  parts,  the  most  con- 
spicuous elements  are  sensations.  We  receive  a  sensation  of 
green  when  looking  at  the  lawn,  a  sensation  of  sour  when  eat- 
ing a  pickle,  a  sensation  of  pain  when  we  burn  our  hand,  and 
sensations  of  movement  when  we  walk. 

Sensations  require  the  stimulation  of  sense  organs  and 
the  conduction  of  nervous  impluses  to  the  sensory  areas  of  the 
cortex.  Sensations  may  be  divided  into  classes  according  to  the 
kind  of  sense  organs  involved.  Thus  we  speak  of  visual  sen- 
sations, auditory  sensations,  or  olfactory  sensations.  They 
may  also  be  distinguished  according  to  their  qualities.  A  color 
may  have  such  a  quality  as  red  or  green.  A  taste  may  have 
the  quality  sour  or  bitter.  Sounds  may  be  high  pitched  or  low 
pitched.  Among  these  qualities  degrees  of  likeness  and  dif- 
ference may  be  distinguished.  Blue  seems  more  like  green 
than  like  red.  Each  different  quality  of  sensation  is  likely  to 
be  accompanied  by  a  characteristic  group  of  responses. 

The  qualities  of  tonal  sensations  may  be  ranged  in  a  con- 
tinuous series.  Any  tone  may  be  assigned  a  place  within  the 
pitch  scale,  and  we  can  pass  from  any  one  pitch  to  any  other 
througs  imperceptibly  small  gradations.  Other  sensations 
cannot  be  arranged  in  such  a  series. 

The  spectrum  arouses  a  series  of  sensations  which  has 
some  resemblance  to  the  pitch  scale,  yet  all  but  a  few  of  these 
sensations  are  analyzable  into  two  components.  The  only  colors 
which  cannot  be  introspectively  analyzed  are  red,  yellow, 
green,  and  blue,  and  there  is  only  one  pure  red,  one  pure  yellow, 


CONSCIOUSNESS  169 

one  pure  green,  and  one  pure  blue.  Other  colors  seem  to  have 
more  than  one  quality. 

The  unanalyzable  colors  are  sometimes  called  "physio- 
logical" colors  because  each  is  supposed  to  be  the  sensation 
resulting  from  a  certain  kind  of  stimulation  of  a  certain  kind 
of  sense  organ.  Almost  all  people  agree  in  their  identification 
of  these  physiological  colors  as  points  in  the  spectral  series. 
Any  deviation  from  these  points  brings  us  to  a  color  which 
seems  to  be  a  mixture  of  two  physiological  colors.  Thus,  al- 
though we  speak  of  a  series  of  greens  in  the  spectrum,  these 
may  be  divided  into  blue-greens  and  yellow-greens  which  lie 
on  either  side  of  the  physiological,  or  unanalyzable,  green. 

A  continuous  qualitative  series  free  from  blends  is  not 
possible  in  sensations  of  vision,  odor,  taste,  touch,  warmth, 
cold,  pain,  movement,  or  in  the  organic  sensations. 

In  the  various  combinations  of  pure  sensation  found  in 
the  consciousness  of  a  given  moment  there  are  degrees  of 
fusion  or  blending.  Two  sensations  may  so  blend  that  only 
careful  introspection  will  analyze  them.  A  note  and  its  octave 
sounded  together  on  tuning  forks,  or  the  touch  and  tempera- 
ture stimulation  from  a  cold  metal  object,  give  such  blended 
sensations. 

Two  sensations  occuring  at  the  same  time  may  fail  to 
blend  and  may  appear  quite  separate  and  distinct.  The  color 
and  odor  of  a  flower  do  not  blend,  though  they  are  experienc- 
ed together.  Introspective  analysis  of  a  sensation  compound 
is  possible  only  when  its  component  sensations  have  been  ex- 
perienced separately. 

Sensations  may  combine  not  as  blends  but  in  the  slightly 
less  intimate  association  of  patterns.  Sensation  patterns  are 
produced  by  an  aggregation  of  objectively  separate  stimuli, 
such  as  the  parts  of  a  picture,  or  the  simultaneous  bending  of 
many  joints.  The  objective  stimuli  may  also  operate  not  at 
the  same  time  but  in  succession,  as  when  a  melody  is  played, 
a  sentence  uttered,  or  a  golf  stroke  executed.    Any  combina- 


170  CONSCIOUSNESS 

tion  of  easily  separable  sensations  which  is  consciously  felt 
to  be  a  whole  is  called  a  pattern. 

Sensations  have  duration,  and  this  corresponds  roughly 
to  the  duration  of  the  stimulus. 

The  intensity  of  sensation  depends  chiefly  upon  the  in- 
tensity of  the  stimulus.  There  is  a  liminal  threshold  for  sen- 
sation just  as  there  is  for  responses,  and  the  sensation  does  not 
occur  unless  the  stimulus  is  of  a  certain  intensity.  In  Weber's 
law  the  term  "sensation"  may  be  substituted  for  "response." 

Summation  effects  are  observable  in  sensation  as  well  as 
in  responses,  and  are  brought  about  by  the  repetition  of  sub- 
liminal stimuli  at  short  intervals.  A  sound  which  is  too  faint 
to  be  heard  when  it  occurs  once  may  be  heard  when  it  is  rapid- 
ly repeated  several  times. 

Sensations  manifest  initial  torpor.  After  listening  to  a 
watch  we  may  hear  it  at  a  greater  distance  than  was  origin- 
ally possible.  This  is  probably  not  wholly  the  result  of  an  ad- 
justment of  the  sense  organ. 

Continuous  stimulation  results  in  the  fatigue  of  sensation, 
and  is  greater  in  the  case  of  odor,  taste,  and  touch  than  in  the 
case  of  pain. 

The  threshold  of  sensation  may  be  altered  in  positive  and 
in  negative  adaptation  in  much  the  same  way  that  the  that  the 
threshold  of  response  is  modified.  The  repetition  of  a  sub- 
liminal stimulus,  that  is,  one  which  is  not  sufficiently  intense 
to  arouse  a  response,  raises  the  threshold  for  both  sensation 
and  response.  When  a  stimulus  which  is  above  the  threshold 
is  repeated  to  the  point  where  fatigue  interferes  with  the  re- 
sponse, both  the  response  threshold  and  the  sensation  threshold 
may  be  permanently  raised.  When  a  response  threshold  has 
been  permanently  raised  as  the  result  of  the  repeated  action 
of  an  inhibiting  stimulus,  the  threshold  of  sensation  will  be 
raised  also. 

An  ascetic  is  originally  prevented  from  enjoying  the  lux- 
uries of  life  by  the  influence  of  his  austere  companions.     If 


CONSCIOUSNESS  171 

he  remains  an  ascetic  it  is  because  one  of  two  things  has  hap- 
pened. He  has  either  come  to  disregard  the  things  of  the  flesh, 
in  which  case  he  develops  negative  adaptation,  both  of  sensa- 
tion and  of  response,  to  these  situations,  or  these  situations 
have  produced  in  him  a  conditioned  response  of  active  anta- 
gonism, in  which  case  his  threshold  of  sensation  is  lowered 
rather  than  raised. 

Positive  adaption  of  sensation  always  involves  positive 
adaption  of  some  response.  This  may  be  merely  an  increased 
tendency  to  orientation.  On  the  other  hand,  practice  in  res- 
ponding to  situations  may  result  in  a  decreased  intensity  of 
sensation.  That  is,  positive  adaption  of  response  may  be  ac- 
companied by  negative  adaption  of  sensation.  If  we  have  at- 
tained skill  on  the  typewriter  we  may,  when  writing,  be  al- 
most unconscious  of  what  we  are  doing.  This  diminution  of 
consciousness  accompanies  freedom  from  inhibitions. 

Emotion  and  Affection 

Introspective  psychology  has  not  fully  decided  the  ques- 
tion whether  emotional  consciousness  can  be  identified  with 
organic  sensations,  the  results  of  internal  responses.  There  is 
a  growing  tendency,  however,  so  to  regard  them.  Though 
they  are  essentially  sensational,  yet  they  may  be  in  part  made 
up  of  memories  of  past  organic  experiences. 

Among  the  affective  states  of  consciousness,  the  most 
generally  recognized  are  pleasure  and  unpleasure.  These  are 
by  some  regarded  as  qualities  of  sensation,  and  by  others  as 
separate  conscious  elements. 

After-images 

There  is  always  a  short  interval  between  the  stimulation 
of  a  sense  organ  and  the  occurrence  of  the  sensation.  This  time 
is  consumed  in  overcoming  inertia  in  the  sense  organ  and  in  the 
transmission  of  the  impulse  from  sense  organ  to  brain,  and  is 
known  as  the  latent  period  of  sensation.    After  the  stimulus 


172  CONSCIOUSNESS 

ceases,  the  sensation  continues  for  a  very  short  time,  and  this 
interval  between  the  end  of  the  stimulus  and  the  end  of  the 
sensation  is  called  the  period  of  lag  of  the  sensation.  When 
strong  stimuli  are  used  the  period  of  lag  is  greater  than  the 
period  of  latency. 

The  lag  of  sensation  may  be  divided  into  two  parts.  The 
first  is  due  to  the  continued  action  of  the  sense  organ  after  the 
stimulation  has  ceased,  and  is  called  the  positive  after-image. 
A  second  part  following  this  is  probably  due  to  a  similar  mo- 
mentum in  sensory  areas  of  the  brain,  and  is  called  primary 
memory.  This  whole  period  of  lag  may  last  for  but  a  second 
or  two.  It  accounts  in  part  for  our  ability  to  distinguish  two 
tones  of  almost  the  same  pitch  sounded  in  quick  succession, 
when  this  would  be  impossible  if  a  longer  time  intervened 
between  the  two.  It  also  accounts  for  continuous  sensation 
from  the  intermittent  stimulation  of  a  motion  picture. 

After  primary  memory  has  disappeared,  what  is  known 
as  a  memory  image  may  appear  in  consciousness.  Such  im- 
ages may  occur  many  years  subsequent  to  the  original  sen- 
sation. Some  people  retain  clear  images  of  childhood  exper- 
iences and  probably  everyone  has  memory  images  to  a  greater 
or  less  extent,  although  there  are  great  individual  differ- 
ences in  this  kind  of  retention.  In  general,  the  memory  im- 
age is  clearer  for  recent  experiences,  for  experiences  that  are 
novel,  for  experiencs  that  are  emotionally  reenforced,  and  for 
experiences  that  have  been  long  continued.  A  day  spent  over 
the  microscope  is  usually  followed  by  clear  memory  images  of 
the  material  studied.  We  remember  vividly  an  accident  or  a 
hair  breadth  escape,  our  first  kiss  or  our  first  day  at  school,  the 
hospital  room  in  which  we  spent  two  weeks,  or  the  pocket 
knife  which  we  carried  for  years.  In  brief,  our  memory  im- 
ages are  clear  in  proportion  to  the  recency  and  duration  of  the 
original  experiences  and  in  proportion  to  the  attention  which 
was  given  to  them. 


CONSCIOUSNESS  173 

Memory  images  and  ideas  are  never  wholly  divorced  from 
response  tendencies.  Action  may  or  may  not  follow  thought, 
but  consciousness  is  most  in  evidence  while  a  response  is  pend- 
ing. Delayed  responses  are  usually  attended  by  a  rich  con- 
scious experience.  When  responses  follow  immediately  upon 
stimulation,  sensations  are  usually  shorter  lived  and  do  not 
wholly  lose  their  initial  torpor. 

Association  of  Ideas 

Before  the  science  of  behavior  was  developed,  certain  laws 
of  association  were  formulated  to  describe  the  origin  of  the 
sequence  of  ideas.  These  laws  state  that  in  any  train  of  thought 
one  idea  follows  another  only  when  the  experiences  from  which 
these  ideas  result  have  occured  in  certain  relationships.  It  was 
shown  that  if  two  experiences  occur  simultaneously  or  in  im- 
mediate succession,  one  of  them,  being  repeated  either  as  a  sen- 
sory experience  or  as  a  memory,  was  capable  of  calling  up 
the  other.  When  we  smell  or  think  of  the  odor  of  roses  we  are 
reminded  of  their  visual  appearance  because  roses  have  been 
smelled  and  seen  at  the  same  time.  When  we  see  lightning  or 
even  think  about  it  the  idea  of  thunder  is  apt  to  come  to  mind. 
The  law  describing  this  sequence  is  that  of  association  by  tem- 
poral contiguity.  The  law  which  describes  associations  as  due 
to  spatial  contiguity  is  reducible  to  the  first  law.  Objects  ex- 
perienced together  in  space  are  also  experienced  together  in 
time.  Even  where  two  expriences,  though  separated  in  time, 
occur  in  the  same  place  and  are  later  associated,  such  as  becom- 
ing acquainted  with  two  individuals  on  separate  occasions  at 
the  house  of  a  friend,  the  matter  may  be  described  as  a  double 
temporal  association.  Cause  and  effect  become  associated 
ideas,  but  only  when  these  ideas  or  the  experiences  which  un- 
derlie them  have  been  known  to  us  simultaneously  or  in  im- 
mediate succession.  Ideas  which  are  similar  tend  to  arouse 
each  other  because  they  are  partially  identical.  Thus  rats  may 
make  us  think  of  mice  on  account  of  their  similar  shape  and 


174  CONSCIOUSNESS 

odor,  though  the  two  have  never  been  seen  together;  cigars 
may  remind  us  of  cigarettes  because  both  are  made  of  tobacco ; 
red  flowers  may  call  to  mind  blood.  Some  consecutive  ideas 
which  seem  to  be  associated  on  the  basis  of  their  similarity 
shows  a  likeness  which  is  not  so  evidently  an  identity  of  element. 
There  is,  for  example,  a  similarity  between  any  musical  note 
and  its  octave,  or  between  the  colors  red  and  violet.  Though  in 
these  cases  the  physical  stimuli  are  far  from  similar,  the  neural 
mechanisms  which  they  stimulate  are  probably  in  part  identical. 

These  laws  of  association  state  for  ideas  what  the  con- 
ditioned response  describes  in  behavior. 

It  was  said  at  the  beginning  of  the  chapter  on  Human 
Motives  that  the  central  nervous  system  is  conceiveably  cap- 
able of  a  self-contained  chain  of  processes  unguided  by  sensory 
stimulation  and  unproductive  of  responses.  Processes  like  this 
may  underlie  the  apparently  random  train  of  thought  found 
in  revery  and  dreams.  It  is  clearly  necessary  that  the  nervous 
energy  for  such  a  chain  of  processes  must  come  from  some- 
where. Is  there  any  reservior  of  energy  which  is  constantly 
available  for  the  maintenance  of  cortical  processes  in  general? 

The  energy  derived  from  looking  at  a  mutton  chop  does 
not  cause  us  to  think  of  the  logarithm  of  seven  because  this 
decimal  was  never  thought  of  while  the  mutton  chop  was  in 
sight.  The  mutton  chop  does  not  contribute  energy  to  corti- 
cal processes  which  have  not  previously  taken  place  while  it 
is  being  looked  at. 

There  are,  however,  certain  forms  of  stimulation  which 
are  almost  constantly  present  and  which,  for  this  reason,  have 
in  the  past  accompanied  practically  all  our  acts  and  all  our 
thoughts.  These  are  the  stimuli  resulting  from  respiration, 
heart  beat,  and  the  muscle  strain  involved  in  maintaining  equi- 
librium and  in  supporting  an  upright  position.  As  these  stimuli 
are  almost  always  acting,  every  act  and  every  thought  is  in 
some  degree  conditioned  upon  them.  Thus  many  cortical  path- 
ways are  open  to  these  impulses  and  the  impulses  are  avail- 


CONSCIOUSNESS  175 

able  to  maintain  many  trains  of  thought.  An  infrequent  stim- 
ulus, such  as  the  mutton  chop,  could  energize  only  a  few  ideas. 

Stimuli  which  are  constantly  present  tend  to  be  followed 
by  so  many  thoughts  and  responses  that  they  are  regularly 
followed  by  no  one  in  particular,  except,  perhaps,  those  which 
have  most  recently  occurred  and  which  thereby  have  a  low 
threshold.  This  may  be  an  explanation  for  the  tendency  of 
recent  thoughts  and  responses  to  recur  in  the  absence  of  spec- 
ialized stimulation.  When  we  go  to  bed  the  organic  stimuli 
which  have  accompanied  our  conscious  experiences  of  today 
are  more  likely  to  revive  memories  of  today  than  memories 
of  yesterday,  because  the  thresholds  of  today's  ideas  are  lower 
than  those  of  a  time  more  remote.  Thus  the  imagery  of  dreams 
is  of  events  of  the  day  just  past  and  of  such  events  of  child- 
hood as  at  that  time  established  for  themselves  a  permanently 
low  threshold.  Thought  is  directed  when  the  stimuli  which 
are  present  have  attached  to  them  only  a  few  definite  re- 
sponses. The  undirected  nature  of  dreams  and  of  waking 
revery  is  to  be  accounted  for  in  large  part  by  the  absence  of 
varied  and  unusual  stimulation  and  by  the  ever  present  resi- 
duum of  organic  stimuli. 

That  most  people  are  unable  to  recall  their  dreams  is 
probably  due  to  the  fact  that  few  experiences  of  waking  life 
were  present  during  the  dream  and  so  cues  for  dream  revival 
are  lacking. 

Imagination 

Just  as  two  response  tendencies  may  combine  into  a  com- 
promise response  when  simultaneously  aroused,  so  two  or 
more  memories  simultaneously  excited  may  be  condensed  into 
a  resultant  idea,  thought,  concept,  or  notion. 

In  imagination  there  come  into  consciousness  thoughts 
and  memory  images  more  or  less  distorted.  This  sequence  of 
imagery  may  seem  wholly  casual  upon  first  inspection,  but  on 
careful  analysis  turns  out  to  be  determined  first  of  all  by  the 
sequence  of  experiences  of  which  these  memories  are  the  "cop- 


176  CONSCIOUSNESS 

ies".  No  memory  is  isolated,  but  is  always  introduced  by  ei- 
ther a  preceding  memory  or  sensation  or  subliminal  stimulus. 
The  image  follows  such  an  event  because  it,  or  the  past  sense 
experience  to  which  it  corresponds,  has  either  previously  fol- 
lowed or  accompanied  this  event. 

The  sequence  of  previous  sense  experiences  is  not  the  only 
factor  in  determining  the  train  of  thought.  The  train  of 
thought  takes  one  direction  at  one  time  and  another  direction 
at  another  time  because  of  the  variability  of  threshold  among 
associated  ideas.  In  behavior,  although  many  responses  are 
attached  to  a  single  stimulus,  only  the  response  of  lowest  thres- 
hold is  elicited.  In  conscious  thought,  although  any  idea  has 
many  assoc:ates,  not  ail  possible  associates  appear  each  time 
the  idea  comes  into  consciousness.  The  threshold  of  any  asso- 
ciate varies  from  time  to  time. 

Attention 

Objectively,  attention  is  the  orientation  of  sense  organs 
toward  the  source  of  stimulation,  the  lowering  of  the  response 
threshold,  and  the  cessation  of  movements  which  do  not  serve 
to  explore  the  object  which  is  attended  to.  Subjectively,  at- 
tention is  the  dominant  presence  in  consciousness  of  either  a 
sense  experience  or  an  idea,  or  of  a  group  of  sensations  or  ideas 
which  have  a  systematic  relation  to  each  other.  As  in  the  case 
of  behavior,  subjective  attention  involves  the  disregard  of  dis- 
tracting stimuli.  The  clearness  of  attentive  consciousness 
which  results  from  the  absence  of  rivalry  is  often  accompanied 
by  sensations  from  the  muscular  contraction  involved  in  orient- 
ation and  preparation  for  action.  These  sensations  account 
for  the  "effort"  which  seems  to  characterize  the  conscious 
state  of  attention. 

The  sensation  or  idea  attended  to  is  determined  by  the 
thresholds  for  the  various  sensations  or  ideas  which  tend  to 
occur,  and  by  the  facilitations  and  inhibitions  which  accom- 
pany them.  One  sensation  or  idea  is  constantly  prevailing  over 


CONSCIOUSNESS  177 

another,  and  this  shifting  of  attention  is  due  to  variations  in 
threshold,  facilitation,  and  inhibition.  After  a  few  seconds 
duration  a  sensation  loses  its  intensity  or  an  image  its  clear- 
ness. This  is  analogous  to  other  forms  of  fatigue  and  invites 
description  in  terms  of  increased  threshold.  After  a  brief  lapse 
of  time  the  threshold  is  again  lowered  and  the  sensation  or  im- 
age may  recur  with  its  original  clearness.  The  pulse  of  at- 
tention usually  lasts  less  than  a  second.  Attention  is  most  evi- 
dent when  there  is  a  balancing  of  response  tendencies. 

Perception 

Perception  as  a  conscious  event  may  be  analyzed  into  two 
parts.  On  the  one  hand  there  are  the  sensations  which  result 
from  sense  organ  stimulation,  and  on  the  other  hand  there  are 
certain  components  which  are  non-sensory  but  which  blend 
with  the  sensations.  These  non-sensory  components  corres- 
pond to  memory  images  though  they  are  too  well  fused  with 
the  sensations  to  permit  of  easy  analysis.  Herbart  gave  the 
name  apperception  to  the  non-sensory  component  of  percep- 
tion. 

One  of  the  common  errors  of  careless  introspection  is  to 
mistake  the  organic  sensations  of  a  perceptual  response  for 
apperception.  When  we  see  a  snake  the  sensory  part  of  the 
perception  is  by  no  means  limited  to  visual  sensations,  but  in- 
cludes sensations  produced  by  muscular  and  visceral  changes. 

The  Unconscious 

Sometimes  we  are  conscious  of  what  we  are  doing,  and 
sometimes  we  are  not.  When  we  enter  a  strange  house,  when 
we  answer  a  difficult  question,  when  we  eat  unfamiliar  food, 
or  when  we  are  overtaken  on  a  railroad  trestle  by  an  approach- 
ing train,  we  are  decidedly  conscious  of  the  situation,  if  not  of 
the  acts  which  we  perform.  Usually  vivid  memories  of  these 
situations  persist  and  we  are  able  to  describe  the  things  which 
have  happened. 


178  CONSCIOUSNESS 

Consciousness  of  our  own  acts  is  most  likely  to  result 
when  we  are  doing  something  to  ourselves,  and  are  thus  in  a 
position  to  observe  our  own  movements  and  our  own  bodily 
states.  When  a  man  removes  a  splinter  from  his  own  finger, 
tries  on  a  new  suit,  or  learns  a  new  dance  step,  he  has  a  clear 
consciousness  not  only  of  the  situation  but  also  of  what  he  is 
doing. 

On  the  other  hand,  a  great  many  situations  and  a  great 
many  acts  do  not  produce  a  state  of  consciousness.  Light  from 
a  multitude  of  surrounding  objects  affects  the  retina,  sounds 
stimulate  the  ear,  and  objects  touch  the  skin,  often  without 
our  knowing  anything  about  it,  even  though  they  may  cause 
responses.  Frequently  we  may  take  articles  from  our  pockets, 
or  walk  some  distance  along  a  familiar  street,  or  draw  dia- 
grams on  the  wall  of  a  telephone  booth,  without  being  at  all 
conscious  of  acting.  The  great  majority  of  the  movements 
we  make  certainly  leave  behind  them  no  conscious  memories 
and  probably  arouse  no  consciousness  at  the  time.  Delayed 
responses,  compromise  responses,  and  blocked  emotional  ex- 
pression nearly  always  have  a  conscious  accompaniment.  In 
other  words,  conscious  states  are  usually  found  when  there  is 
interference  among  response  tendencies. 

Although  acts  unaccompanied  by  consciousness  might  well 
be  called  unconscious  acts,  the  term,  "the  unconscious",  is 
generally  reserved  as  a  classification  and  as  a  somewhat  too 
easy  explanation  for  acts  whose  lack  of  preceding  conscious 
motive,  whose  lack  of  conscious  accompaniment,  or  whose 
lack  of  resulting  conscious  memory  is  a  matter  of  surprise. 
The  man  who  has  a  horror  of  Gothic  windows  but  who  does 
not  know  why,  is  said  to  have  an  unconscious  motive  for  his 
fear.  It  might  possibly  be  discovered  on  investigation  that  as 
a  baby  he  strayed  away  and  was  lost  in  a  gloomy  cathedral, 
but  has  retained  no  conscious  memory  of  this  occurrence. 

Most  of  our  motives  are  unconscious  in  the  sense  that  we 
are  not  aware  of  the  circumstances  under  which  our  reaction 


CONSCIOUSNESS  179 

tendencies  were  established.  We  are  also  unaware  of  the  type 
of  emotional  reenforcement  which  drives  us  to  act  as  we  do. 
The  parlor  maid  who  accidently  breaks  the  ornate  vase,  the 
dusting  of  which  has  often  caused  her  annoyance,  is  supposed 
by  Freud  to  be  actuated  by  a  subconscious  motive  in  her  act  of 
destruction.  Many  psychologists,  however,  are  content  to  des- 
cribe this  occurrence  as  an  awkward  act  resulting  from  the 
conflict  of  two  tendencies,  both  of  which  are  aroused  by  the 
sight  of  the  vase.  One  of  these  is  a  tendency  to  dust  the  object, 
and  the  other  is  a  tendency  to  smash  the  annoying  thing.  It  is 
by  no  means  necessary  to  assume  an  unconscious  mind  which 
plots  evil  against  a  more  righteous  consciousness. 

An  anomalous  lack  of  conscious  accompaniment  is  seen 
in  the  automatic  writing  performed  by  the  hand  of  an  hys- 
teric. He  is  unconscious  of  his  act  and  his  attention  seems 
to  be  fully  engaged  on  other  matters.  This  is  described  as  an 
automatism. 

The  absence  of  memory  for  events  that  would  usually  be 
remembered  is  called  amnesia.  A  man  recently  found  him- 
self on  a  train  bound  for  Seattle.  His  latest  recollection  was 
of  sitting  in  a  barber's  chair  in  his  home  town,  which  event 
had  occured  five  days  previous.  Having  no  memory  of  the 
intervening  period,  he  was  surprised  to  find  himself  possessed 
of  a  railroad  ticket  bought  in  Portland  and  of  four  hundred 
dollars  in  cash,  the  source  of  which  was  unknown  to  him.  Such 
cases  of  amnesia  are  by  no  means  infrequent  and  the  memory 
of  the  forgotten  period  may  often  be  revived  either  spontan- 
eously or  by  psychoanalytic  technique. 


LIST  OF  AUTHORS 

Aristotle :    De  sensu,  436b. 

Blanton:    Behavior  of  the  Human  Infant,  Psychological  Review,  1917, 
pages  456-483. 

Cannon:    Bodily  Changes  in  Pain,  Hunger,  Fear,  and  Rage,  N.  Y.  1915. 

Colvin :     The  Learning  Process,  N.  Y.  Macmillan,  1915 

Darwin:    The  Expression  of  the  Emotions  in  Mam  and  in  Animals,  N. 
Y.,  1892. 

Ebbinghaus :    Memory.     Publications  of  Teachers  College,  Columbia. 

Goldmark:     Fatigue  and  Efficiency,  Russell   Sage  Foundation,   1912. 
Page  71. 

Herrick :     Introduction  to  Neurology. 

Hill,  Re  jail,  and  Thorndike :    Practice  in  the  Case  of  Typewriting,  Ped. 
Sem.  1913,  pages  516-529. 

Holmes:    Studies  in  Animal  Behavior,  Boston,  Badger,  1916. 

Hunter,  W.  S. :    The  Delayed  Reaction  in  Animals  and  Children,  Animal 
Behavior  Monographs,  1913,  No.  1. 

James:     Principles  of  Psychology,  N.  Y.  1890. 

Ladd  and  Woodworth :     Elements  of  Physiological  Psychology,  N.  Y. 
1911. 

Lashley:    A  Simple  Maze;  with  data  on  the  relation  of  the  distribution 
of  practice  to  the  rate  of  learning.    Psychobiology,  1918,  335-367. 

Lashley:    The  Acquisition  of  Skill  in  Archery,  Carnegie  Inst.,  1915. 

Lyon  :    Memory  and  the  Learning  Process,  Baltimore,  1917. 

Locke  :    Essay  Concerning  Human  Understanding. 

Meumann,  K. :   Psychology  of  Learning,  N.  Y.,  1913. 

Pechstein  :   Whole  vs  Pari  Methods  in  Motor  Learning,  Psychological 
Monographs,  1917. 

(180) 


LIST  OF  AUTHORS  181 

Peterson  and  Rainey:     Beginnings  of  Mind  in  the  New  Born,  in  the 

Bulletin  of  the  Lying-in  Hospital  of  the  City  of  New  York,  1910. 
Preyer,  W. :    The  Mind  of  the  Child,  N.  Y.,  1905. 

Pyle:    Economical  Learning,  Journal  of  Educational  Psychology,  1913, 
pages  148-158. 

Pyle  and  Snyder:    The  Most  Economical  Unit  for  Committing  to  Mem- 
ory, Journal  of  Educational  Psychology,  1911,  pages  133-142. 

Sherrington :     The  Integrative  Action  of  the  Nervous  System,  N.  Y., 
1906. 

Smith,  Stevenson :    The  Limits  of  Educ ability  in  Paramoecium,  Journal 
of  Comp.  Neur.  and  Psychol.  1908,  page  503. 

Spalding:    in  Nature,  vol.  12,  page  507. 

Thorndike:    Animal  Intelligence,  N.  Y.  Macmillan,  1911. 

Thorndike:    Educational  Psychology,  N.  Y.,  1918. 

Thorndike:     Fatigue  in  a  Complex  Function,   Psychological  Review, 
1914,  pages  402-407. 

Thorndike :    Notes  on  Practice,  Im provability,  and  the  Curve  of  Work, 
American  Journal  of  Psychology,  1916,  pages  550-565. 

Triplett :     The  Educatibility  of  the  Perch,  American  Journal  of  Psy- 
chology, vol.  2,  page  419. 

Twitmyer:    A  Study  of  the  Knee  Jerk,  Phila.,  1902. 

Watson:    Journal  of  Experimental  Psychology,  1920. 

Watson :    Psychology  from  the  Standpoint  of  a  Behaviorist,  Phila.,  1919. 

Woodworth:    Dynamic  Psychology,  N.  Y.,  1918. 


14  DAY  USE 

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